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Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2015
Document Information [Line Items]
Document Type	8-K/A
Amendment Flag	true
AmendmentDescription	On September 4, 2015, Catalyst Biosciences, Inc. (the “Company”), filed an Amendment No. 1 on Form 8-K/A amending and restating in its entirety the Catalyst Biosciences, Inc. Form 8-K originally filed with the Securities and Exchange Commission on August 20, 2015 (together, the “Prior Filings”) and reporting, among other items, that on August 20, 2015, the Company completed its business combination with Catalyst Bio, Inc., formerly known as Catalyst Biosciences, Inc. (“Old Catalyst”). This Amendment No. 2 on Form 8-K/A ( “Amendment No. 2”), amends the Prior Filings to provide (i) the historical audited and unaudited financial statements of Old Catalyst and (ii) the pro forma condensed combined financial information as required by Items 9.01(a) and 9.01(b) of Form 8-K, respectively. Such financial information was excluded from the Prior Filings in reliance on the instructions to such Items.
Document Period End Date	Jun. 30, 2015
Trading Symbol	CBIO
Entity Registrant Name	CATALYST BIOSCIENCES, INC.
Entity Central Index Key	0001124105

Condensed Balance Sheets - USD ($)	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 2,306,000	$ 1,543,705	$ 2,828,431
Deposits		278,604
Restricted cash	107,000	50,000	50,000
Accounts receivable	87,000	95,063	96,092
Prepaid and other current assets	178,000	102,900	201,778
Total current assets	2,678,000	2,070,272	3,176,301
Property and equipment, net	653,000	910,981	1,765,184
Deposits			278,604
Intangible assets, net of amortization			54,102
Total noncurrent assets		910,981	2,097,890
Total assets	3,331,000	2,981,253	5,274,191
Current liabilities:
Accounts payable	1,541,000	248,589	354,437
Accrued compensation	486,000	280,730	233,918
Other accrued liabilities	329,000	30,000	78,812
Deferred revenue, current portion	438,000	1,750,000	1,187,500
Deferred rent		26,314	156,215
Convertible notes - related parties	1,458,000
Total current liabilities	4,252,000	2,335,633	2,010,882
Deferred revenue, noncurrent portion	510,000	729,167	1,604,167
Deferred rent, noncurrent portion			26,308
Warrant liability	270,000	391,361
Total noncurrent liabilities		1,120,528	1,630,475
Total liabilities	5,032,000	3,456,161	3,641,357
Stockholders' deficit:
Common stock value	9,710,000	9,710	9,559
Additional paid-in capital	7,009,000	6,913,042	6,643,780
Accumulated deficit	(120,857,000)	(116,274,661)	(109,661,406)
Total Stockholders' Deficit	(113,838,000)	(109,351,909)	(103,008,067)
Total Liabilities and Stockholders' Deficit	3,331,000	2,981,253	5,274,191
Series AA Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	7,327,166	7,327,166	7,327,166
Series BB Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	29,356,728	29,356,728	29,356,728
Series BB-1 Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	8,999,999	8,999,999	8,999,999
Series CC Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	58,175,835	58,175,835	58,175,835
Series D Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	781,173	781,173	781,173
Series E Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	4,236,100	4,236,100
Series F Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	3,260,000
Convertible Preferred Stock
Convertible preferred stock:
Preferred stock value	$ 112,137,000	$ 108,877,001	$ 104,640,901

Condensed Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Preferred stock, shares authorized		88,469,871
Preferred stock, shares issued		87,405,011
Preferred stock, shares outstanding		87,405,011
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized	160,000,000	110,000,000	104,000,000
Common stock, shares issued	9,810,572	9,710,572	9,560,572
Common stock, shares outstanding	9,810,572	9,710,572	9,560,572
Series AA Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	7,327,166	7,327,166	7,327,166
Preferred stock, shares issued	7,327,166	7,327,166	7,327,166
Preferred stock, shares outstanding	7,327,166	7,327,166	7,327,166
Preferred stock, aggregate liquidation preference	$ 7,327,166	$ 7,327,166	$ 7,327,166
Series BB Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	23,104,618	23,104,618	23,104,618
Preferred stock, shares issued	23,104,618	23,104,618	23,104,618
Preferred stock, shares outstanding	23,104,618	23,104,618	23,104,618
Preferred stock, aggregate liquidation preference	$ 29,356,728	$ 29,356,728	$ 29,356,728
Series BB-1 Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,978,477	5,978,477	5,978,477
Preferred stock, shares issued	5,978,477	5,978,477	5,978,477
Preferred stock, shares outstanding	5,978,477	5,978,477	5,978,477
Preferred stock, aggregate liquidation preference	$ 8,999,999	$ 8,999,999	$ 8,999,999
Series CC Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	46,429,980	46,429,980	46,429,980
Preferred stock, shares issued	46,429,980	46,429,980	46,429,980
Preferred stock, shares outstanding	46,429,980	46,429,980	46,429,980
Preferred stock, aggregate liquidation preference	$ 58,993,933	$ 58,993,933	$ 58,993,933
Series D Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	629,630	629,630	629,630
Preferred stock, shares issued	629,630	629,630	629,630
Preferred stock, shares outstanding	629,630	629,630	629,630
Preferred stock, aggregate liquidation preference	$ 4,000,039	$ 4,000,039	$ 4,000,039
Series E Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001	$ 0.001
Preferred stock, shares authorized	4,918,918	5,000,000
Preferred stock, shares issued	3,935,140	3,935,140
Preferred stock, shares outstanding	3,935,140	3,935,140
Preferred stock, aggregate liquidation preference	$ 9,999,978	$ 9,999,978
Series F Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	4,000,000	0
Preferred stock, shares issued	2,623,650	0
Preferred stock, shares outstanding	2,623,650	0
Preferred stock, aggregate liquidation preference	$ 16,668,000

Condensed Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Contract revenue	$ 859,000	$ 297,000	$ 1,531,000	$ 594,000	$ 1,812,500	$ 523,308
Operating expenses:
Research and development	1,322,000	1,287,000	2,705,000	2,535,000	5,266,571	6,556,958
General and administrative	1,738,000	1,220,000	4,060,000	2,132,000	4,055,633	4,086,300
Total operating expenses	3,060,000	2,507,000	6,765,000	4,667,000	9,322,204	10,643,258
Loss from operations	(2,201,000)	(2,210,000)	(5,234,000)	(4,073,000)	(7,509,304)	(10,119,950)
Change in fair value of warrant liability	516,000		595,000		354,524
Interest expense - related parties	(39,000)		(39,000)
Other Income		135,000	96,000	263,000	541,925	153,613
Net loss	$ (1,724,000)	$ (2,075,000)	$ (4,582,000)	$ (3,810,000)	$ (6,613,255)	$ (9,966,337)
Net loss per common share, basic and diluted	$ (0.18)	$ (0.22)	$ (0.47)	$ (0.40)
Shares used to compute net loss per common share, basic and diluted	9,810,572	9,572,110	9,780,959	9,566,373

Statements of Convertible Preferred Stock and Stockholders Deficit - USD ($)	Total	Series CC Convertible Preferred Stock	Convertible Preferred Stock Amount	Convertible Preferred Stock Amount Series CC Convertible Preferred Stock	Convertible Preferred Stock Amount Series D Preferred Stock	Convertible Preferred Stock Amount Series E Preferred Stock	Common Stock Amount	Additional Paid-In Capital	Accumulated Deficit
Balances (in shares) at Dec. 31, 2012							9,560,572
Balances at Dec. 31, 2012	$ (93,339,550)						$ 9,559	$ 6,345,960	$ (99,695,069)
Balances at Dec. 31, 2012			$ 98,898,841
Balances at Dec. 31, 2012			78,932,729
Stock based compensation expense associated with vesting of stock award	297,820							297,820
Issuance of convertible preferred stock to investors				$ 4,960,887	$ 781,173
Issuance of convertible preferred stock to investors				3,907,512	629,630
Net and comprehensive loss	(9,966,337)								(9,966,337)
Balances (in shares) at Dec. 31, 2013							9,560,572
Balances at Dec. 31, 2013	(103,008,067)						$ 9,559	6,643,780	(109,661,406)
Balances at Dec. 31, 2013		$ 58,175,835	$ 104,640,901
Balances at Dec. 31, 2013		46,429,980	83,469,871
Stock based compensation expense associated with vesting of stock award	244,413							244,413
Stock options exercises for cash ($.05-$.40) (in shares)							150,000
Stock options exercises for cash ($.05-$.40)	25,000						$ 151	24,849
Issuance of convertible preferred stock to investors						$ 4,236,100
Issuance of convertible preferred stock to investors						3,935,140
Net and comprehensive loss	(6,613,255)								(6,613,255)
Balances (in shares) at Dec. 31, 2014							108,877,001
Balances at Dec. 31, 2014	$ (109,351,909)						$ 9,710	$ 6,913,042	$ (116,274,661)
Balances at Dec. 31, 2014		$ 58,175,835	$ 108,877,001
Balances at Dec. 31, 2014	87,405,011	46,429,980	87,405,011
Balances at Jun. 30, 2015	$ (113,838,000)
Balances at Jun. 30, 2015		$ 58,175,835
Balances at Jun. 30, 2015		46,429,980

Statements of Convertible Preferred Stock and Stockholders Deficit (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Exercise price per share	$ 0.05
Exercise price per share	0.40
Series CC Convertible Preferred Stock
Convertible preferred stock, shares issued per share value		$ 1.2706
Net of issuance costs		$ 3,998
Series D Preferred Stock
Convertible preferred stock, shares issued per share value		$ 1.2706
Net of issuance costs		$ 18,832
Series E Preferred Stock
Convertible preferred stock, shares issued per share value	$ 1.2706
Net of issuance costs	$ 27,843

Condensed Statements of Cash Flows - USD ($)	6 Months Ended		12 Months Ended
Condensed Statements of Cash Flows - USD ($)	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Operating Activities
Net loss	$ (4,582,000)	$ (3,810,000)	$ (6,613,255)	$ (9,966,337)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	83,000	133,000	244,413	297,820
Depreciation and amortization	258,000	439,000	679,595	974,017
Loss on disposal of fixed assets		77,000	77,491
Non-cash interest expense and amortization of debt discount	39,000
Change in fair value of warrant liability	(595,000)		(354,524)
Impairment of patent asset			53,219
Changes in operating assets and liabilities:
Accounts receivable	8,000	14,000	1,029	(51,263)
Prepaid and other current assets	203,000	67,000	98,878	53,950
Accounts payable	1,292,000	34,000	(105,848)	11,162
Accrued compensation and other accrued liabilities	504,000	17,000	(2,000)	(246,716)
Deferred rent	(26,000)	(77,000)	(156,209)	(138,013)
Deferred revenue	(1,531,000)	(594,000)	(312,500)	2,791,667
Net cash flows used in operating activities	(4,347,000)	(3,700,000)	(6,389,711)	(6,273,713)
Investing Activities
Change in restricted cash	(57,000)
Purchases of property and equipment				(41,365)
Proceeds from sale of fixed assets		98,000	98,000
Net cash flows (used in)/provided by investing activities	(57,000)	98,000	98,000	(41,365)
Financing Activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	3,260,000	4,983,000	4,981,985	5,742,060
Proceeds from issuance of convertible notes and warrants to related parties	1,893,000
Proceeds from exercise of options			25,000
Proceeds from the issuance of common stock upon exercise of stock options	13,000	20,000
Net cash flows provided by financing activities	5,166,000	5,003,000	5,006,985	5,742,060
Net decrease in cash and cash equivalents	762,000	1,401,000	(1,284,726)	(573,018)
Cash and cash equivalents at beginning of period	1,543,705	2,828,431	2,828,431	3,401,449
Cash and equivalents at end of period	$ 2,306,000	$ 4,229,000	$ 1,543,705	$ 2,828,431

Summary of Significant Accounting Policies

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

Unaudited Interim Financial Information

The interim condensed balance sheet as of June 30, 2015, and the statements of operations and comprehensive loss for the three and six months ended June 30, 2015 and 2014, and cash flows for the six months ended June 30, 2015 and 2014 are unaudited. The unaudited interim financial statements have been prepared on the same basis as the annual financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position as of June 30, 2015 and its results of operations and cash flows for the three and six months ended June 30, 2015 and 2014. The financial data and the other information disclosed in these notes to the financial statements related to the three- and six-month periods are also unaudited. The results of operations for the six months ended June 30, 2015 are not necessarily indicative of the results to be expected for the year ending December 31, 2015 or for any other future annual or interim period. The balance sheet as of December 31, 2014 included herein was derived from the audited financial statements as of that date. These financial statements should be read in conjunction with the Company’s audited financial statements.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, convertible preferred stock and related warrants, common stock and stock-based compensation. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company invests its excess cash in bank deposits, consisting primarily of money market mutual funds. The Company considers all highly liquid investments with original maturities of three months or less when purchased to be cash equivalents.

Restricted Cash

At June 30, 2015 and December 31, 2014, the Company had restricted cash of $107,000 and $50,000, respectively. The restricted cash serves as collateral for the Company’s corporate credit card and deposit for its facility lease.

Fair Value Measurements

Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three tier fair value hierarchy for disclosure of fair value measurements as follows:

•

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.

•

Level 2: Observable inputs other than quoted prices included within Level 1, such as quoted prices for similar assets or liabilities in active markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

•

Level 3: Unobservable inputs that are supported by little or no market data. Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date.

As of June 30, 2015 and December 31, 2014, the Company’s highly liquid money market funds included within cash equivalents are financial assets that are valued using Level 1 inputs. Liabilities that are measured at fair value consist of the warrant for convertible preferred stock that utilizes Level 3 inputs.

The fair value of the liability related to the warrant for convertible preferred stock is measured using the Black-Scholes option-pricing model. Inputs used to determine the estimated fair value of the warrant liability include the estimated fair value of the underlying convertible preferred stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, and expected dividends on and expected volatility of the price of the underlying preferred stock.

The following table sets forth the Company’s assets and liabilities that were measured at fair value and the level of the inputs used to value those assets and liabilities within the fair value hierarchy (in thousands):


	Level 1		Level 2		Level 3			Total
As of June 30, 2015:
Money market funds	$	2,244	$	—	$	—		$	2,244
Warrant for convertible preferred stock liability		—		—		(270	)		(270	)

Total	$	2,244	$	—	$	(270	)	$	1,974


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,544	$	—	$	—		$	1,546
Warrant for convertible preferred stock liability		—		—		(391	)		(391	)

Total	$	1,544	$	—	$	(391	)	$	1,155

The following table present the activity for liabilities measured at estimated fair value using unobservable inputs for the six months ended June 30, 2015 (in thousands):


	Warrant for Convertible Stock
Beginning balance of warrant liability at December 31, 2014	$	391
Fair value of warrants issued during the period		474
Change in estimated fair value		(595	)

Ending balance of warrant liability at June 30, 2015	$	270

Comprehensive Loss

Comprehensive loss is composed of net loss and other comprehensive income or loss. To date, the Company has not had any significant transactions that are required to be reported in comprehensive loss other than the net loss from operations.

Revenue Recognition

The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments; full time equivalent based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

Revenue related to collaborations is recognized when the four basic criteria for revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) transfer of technology has been completed or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured.

Revenue recognition for multiple element revenue arrangements will have deliverables associated with the arrangement divided into separate units of accounting provided that (i) a delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. As a biotechnology company with unique and specialized technological undelivered performance obligations associated with its collaborations, the Company’s multiple element arrangements most often involve deliverables and consideration that do not meet the criteria for having stand-alone value.

Deliverables and performance obligations are accounted for under a single unit of accounting when they do not have stand-alone value and the related consideration is recognized as revenue over the estimated period of when the performance obligations are to be performed. The revenue is recognized on a proportional performance basis when the levels of the performance obligations under an arrangement can be reasonably estimated and on a straight-line basis when they cannot.

The Company’s collaboration agreements entitle it to additional payments upon the achievement of performance-based milestones related to product development, regulatory actions and commercial events in certain geographic areas. Milestones that are not deemed probable or that are tied to counter-party performance are not included in the Company’s revenue until the performance conditions are met. If a collaborative agreement milestone is deemed to be substantive, as defined in the accounting rules, the Company is permitted to recognize revenue related to the milestone payment in its entirety.

In the event milestones are deemed non-substantive, the Company recognizes, and defers if applicable, payments for the achievement of such non-substantive milestones over the estimated period of performance applicable to each collaborative agreement using the proportional performance method or on a straight-line basis, as appropriate.

Collaborative agreement amounts received prior to satisfying revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. Deferred revenue is recorded on the Company’s balance sheet as short-term or long-term based on its best estimate as to when such revenue will be recognized. Short-term deferred revenue consists of amounts that the Company expects to recognize as revenue in the next 12 months. Amounts that the Company expects will not be recognized prior to the next 12 months are classified as long-term deferred revenue.

The Company’s performance obligations under its collaboration arrangements also consist of participation on steering committees and the performance of other research and development and business development services. The timing for satisfying these performance obligations can be difficult to estimate and can be subject to change over the course of these agreements. A change in the estimated timing for satisfying the Company’s performance obligations could change the timing and amount of revenue that the Company recognizes and records in future periods.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development costs consist of payroll and other personnel-related expenses, laboratory supplies and reagents, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreements, certain specific expenditures are reimbursed by third parties. During the three months ended June 30, 2015 and 2014 and the six months ended June 30, 2015 and 2014, the Company recorded a reduction to research and development expenses of $87,000, $82,000, $469,000 and $195,000 respectively.

Net Loss per Share

Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per share, since the effects of potentially dilutive securities are antidilutive given the net loss of the Company.

1. Summary of Significant Accounting Policies

Nature of Operations and Basis of Presentation

Catalyst Biosciences, Inc. (the Company or Catalyst), was incorporated in the state of Delaware on August 5, 2002. The Company is a clinical-stage biotechnology company focused on engineering proteases as therapeutics for hemophilia, hemeostasis, compliment-mediated diseases, and other unmet medical needs. Its facilities are located in South San Francisco, California. The Company’s current customers, engaged principally through collaborations are other pharmaceutical and biotechnology companies, who are also engaged in developing and commercializing therapies for patients in the areas of hemophilia and compliment-mediated diseases.

Liquidity

The Company has incurred cumulative net losses of $116.3 million through December 31, 2014 and negative cash flows from operating activities and expects to continue to incur losses for the next several years. Management plans to continue to finance the Company’s operations with a combination of revenues from technology licenses, corporate alliances with pharmaceutical companies, equity issuances, and debt arrangements. The Company’s operating plans and scope of development programs are directly related to the availability of adequate funds. If adequate funds are not available in the future, the Company may be required to delay, reduce the scope of, or eliminate one or more of its development programs and/or need to reevaluate its operating plans.

These factors raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying financial statements have been prepared assuming the Company will continue to operate as a going concern, which contemplates the realization of assets and the settlement of liabilities in the normal course of business. The financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the outcome of this uncertainty related to the Company’s ability to continue as a going concern.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Such management estimates include the warrant for convertible preferred stock. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Operating Expenses

Research and development costs are expensed as incurred. Research and development costs consist of payroll and personnel expenses, laboratory supplies and reagents, contract research and development services, and consulting costs, as well as allocations of facilities and other overhead costs. Under the Company’s collaboration agreements, certain specific expenditures are reimbursed by third parties. During the years ended December 31, 2014 and 2013, $381,465 and $175,713, respectively were reimbursed to the Company. Payments received as direct reimbursement of specific expenditures are recorded as a reduction to those expenses.

Cash and Cash Equivalents

Restricted Cash

At December 31, 2014 and 2013, the Company had restricted cash of $50,000 required as collateral for the Company’s corporate credit card.

Fair Value Measurements

The Company follows Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 820 (ASC 820), Fair Value Measurements. ASC 820 establishes a fair value hierarchy that categorizes observable and unobservable inputs used to measure fair value into three levels, which are described below:

•

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.

•

As of December 31, 2014 and 2013, the Company’s highly liquid money market funds included within cash equivalents are financial assets that are valued using Level 1 inputs and the Company does not have any financial instruments utilizing level 2 or level 3 inputs. Liabilities that are measured at fair value consist of the warrant for convertible preferred stock that utilizes Level 3 inputs.

The fair value of the warrant for convertible preferred stock is measured using the Black-Scholes option-pricing model. Inputs used to determine the estimated fair value of the warrant include the estimated fair value of the underlying preferred stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates, and expected dividends on and expected volatility of the price of the underlying preferred stock. The Company did not have any significant changes in its valuation techniques related to the valuation of this liability during 2014.

The following table sets forth the Company’s assets that were measured at fair value and the level of the inputs used to value those assets and liabilities within the fair value hierarchy:


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,546,038	$	—	$	—		$	1,546,038
Warrant for convertible preferred stock		—		—		(391,361	)		(391,361	)

Total	$	1,546,038	$	—	$	(391,361	)	$	1,154,677


	Level 1		Level 2		Level 3			Total
As of December 31, 2013:
Money market funds	$	2,710,191	$	—	$	—		$	2,710,191

The following tables present the activity for liabilities measured at estimated fair value using unobservable inputs for the year ended December 31, 2014:


Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Warrant for Convertible Stock
Beginning balance at December 31, 2013	$	—
Issuance of warrants		745,885
Changes in estimated fair value		(354,524	)

Ending balance at December 31, 2014	$	391,361

Comprehensive Loss

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. The Company’s investment policy restricts cash investments to high credit quality, investment grade investments.

The Company believes that it has established guidelines for investment of its excess cash that maintain safety and liquidity through its policies on diversification and investment maturity. The Company is exposed to credit risk in the event of default by the institutions holding the cash and cash equivalents to the extent of the amounts recorded on the balance sheets. The Company’s accounts receivable at December 31, 2014 was $95,063, of which $79,857 was due from Pfizer Inc., and $15,206 was due from ISU Abxis. The Company has incurred no credit losses to date. The Company does not require collateral from its collaboration partners.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation. Depreciation is provided using the straight-line method over the estimated useful lives of the respective assets, which are three years for computer equipment and software, and three to seven years for laboratory and office equipment, furniture and leasehold improvements.

Intangible Assets

Intangible assets represent patent rights purchased in 2009 in the amount of $70,567 that were being amortized over their estimated useful life of 20 years, or life of the patent whichever is shorter, using the straight-line method. Annual amortization was $883 and $3,528 for 2014 and 2013, respectively. The Company abandoned this patent in 2014. No further amortization is necessary. The total amortized through 2014 was $17,348 and the remaining $53,219 was written off to amortization expense during 2014 in the accompanying statements of operations.

Revenue Recognition

The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments; full time equivalent (FTE) based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

The Company has entered into collaboration agreements with Wyeth (now Pfizer), MedImmune, Centocor and ISU Abxis. For the annual periods ending December 31, 2014 and 2013, only collaborations with Pfizer and ISU Abxis were active. Revenue related to these collaborations is recognized when the four basic criteria for revenue recognition are met: (1) persuasive evidence of an arrangement exists; (2) transfer of technology has been completed or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured.

Revenue recognition for multiple revenue arrangements will have deliverables associated with the arrangement divided into separate units of accounting provided that (i) a delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially in the control of the vendor. As a biotechnology company with unique and specialized technological undelivered performance obligations associated with its collaborations, the Company’s multiple element arrangements most often involve deliverables and consideration that do not meet the criteria for having stand alone value.

Such deliverables and consideration must be accounted for under a single unit of accounting along with other arrangement deliverables and consideration that do not have stand-alone value and are recognized as revenue over the estimated period of when the performance obligations are to be performed. The revenue is recognized on a proportional performance basis when the levels of the performance obligations under an arrangement can be reasonably estimated and on a straight-line basis when they cannot.

The non-refundable, up-front or license maintenance payments associated with the Company’s collaboration agreements do not have stand-alone value to the collaborator and accordingly, are recognized only when standard basic criteria for revenue recognition are met, e.g. the Company has a contractual right to receive such payment, the contract price is fixed and determinable, the collection of the resulting receivable is reasonably assured and the Company has no further performance obligations under the agreement.

Collaborative agreement amounts received prior to satisfying revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. Deferred revenue is recorded on our balance sheet as short-term or long-term based on our best estimate as to when such revenue will be recognized. Short-term deferred revenue consists of amounts that we expect to recognize as revenue in the next 12 months. Amounts that we expect will not be recognized prior to the next 12 months are classified as long-term deferred revenue.

The estimate of deferred revenue also reflects management’s estimate of the periods of the Company’s involvement, or performance obligations, in our collaborations. The Company’s performance obligations under these collaborations consist of participation on steering committees and the performance of other research and development and business development services. The timing for satisfying these performance obligations can be difficult to estimate and can be subject to change over the course of these agreements. A change in the estimated timing for satisfying the Company’s performance obligations could change the timing and amount of revenue that we recognize and record in future periods. The estimated period of the Company’s performance obligations under its active collaboration agreements are currently assessed to conclude August, 2015 under the Pfizer collaboration and August, 2017 under our collaboration with ISU Abxis (see Note 7, Collaborations). As of December 31, 2014, the Company had short-term and long-term deferred revenue of $1,750,000 and $729,167, respectively, related to collaborations. As of December 31, 2013, the Company had short-term and long-term deferred revenue of $1,187,500 and $1,604,167, respectively, related to collaborations.

Income Taxes

Income taxes are computed using the liability method. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

It is the Company’s policy to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.

The Company follows the authoritative guidance on accounting for uncertainty in income taxes. This guidance prescribes a more-likely-than-not threshold for financial statement recognition and measurement of a tax position taken in the Company’s income tax returns. This interpretation also provides guidance on accounting for interest and penalties and associated with tax positions, accounting for income taxes in interim periods and income tax disclosures. The Company’s policy is to recognize interest and penalties related to tax matters in the income tax provision in the Statements of Operations.

As of December 31, 2014 and 2013, the Company had no uncertain tax positions which affected its financial position and its results of operations or its cash flow, and will continue to evaluate for uncertain positions in the future. The open tax years for the Company are December 31, 2011 through December 31, 2014 and are subject to examination by the IRS and other various taxing authorities, generally for three years after tax returns were filed.

Stock-Based Compensation

The Company measures the cost of employee and director services received in exchange for an award of equity instruments based on the fair value-based measurement of the award on the date of grant and recognizes the related expense over the period during which the employee or director is required to provide service in exchange for the award on a straight-line basis.

The Company uses the Black-Scholes option-pricing valuation model to estimate the grant-date fair value-based measurement of stock-based awards. The determination of fair value-based measurements for stock-based awards on the date of grant using an option-pricing model requires management to make certain assumptions regarding a number of variables. The Company records stock-based compensation as compensation expense, net of the estimated impact of forfeited awards. The Company applies a forfeiture rate to stock-based compensation expense using historical data to estimate pre-vesting option forfeitures. The Company estimates forfeitures at the time of grant, and revises those estimates in subsequent periods if actual forfeitures differ materially from those original estimates. As such, the Company recognizes stock-based compensation expense only for those stock-based awards that are expected to vest, over their requisite service period, based on the vesting provisions of the individual grants.

For nonemployee stock-based awards, the measurement date on which the fair value-based measurement of the stock-based award is calculated is equal to the earlier of (i) the date at which a commitment for performance by the counterparty to earn the equity instrument is reached or (ii) the date at which the counterparty’s performance is complete. The Company recognizes stock-based compensation expense for the fair value-based measurement of the nonemployee awards using the Black Scholes option-pricing valuation model and the awards are typically subject to periodic re-measurement over the period that services are rendered.

Deferred Rent

The Company’s facilities lease agreement provides for an escalation of rent payments each year. The Company records rent expense on a straight-line basis over the term of the lease. The difference between the amount of expense recognized and the amount of rent paid is recorded as deferred rent in the accompanying balance sheets.

New Accounting Pronouncement

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. This update states a core principle in that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.

To achieve the core principle, an entity should apply the following steps: 1) identify the contract(s) with the customer; 2) identify the performance obligations in the contract; 3) determine the transaction price; 4) allocate the transaction price to the performance obligation in the contract; and 5) recognize revenue when (or as) the entity satisfies a performance obligation. The amendments in the update are effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Early application is not permitted. The Company is currently assessing the impact of this standard.

In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 requires management to evaluate relevant conditions, events and certain management plans that are known or reasonably knowable that, when considered in the aggregate, raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued, for both annual and interim periods. ASU 2014-15 also requires certain disclosures around management’s plans and evaluation, as well as the plans, if any, that are intended to mitigate those conditions or events that will alleviate the substantial doubt. ASU 2014-15 is effective for fiscal years ending after December 15, 2016. Catalyst is currently evaluating the impact that the adoption of ASU 2014-15 will have on its financial statements and related disclosures.

Reclasssification

Certain reclassifications have been made to the 2013 financial statements to conform to the 2014 presentation.

Property and Equipment

12 Months Ended

Dec. 31, 2014

Property and Equipment

2. Property and Equipment

Property and equipment consisted of the following:


	December 31,
	2014			2013
Laboratory and office equipment	$	5,026,560		$	6,092,206
Furniture		311,218			311,218
Leasehold improvements		1,515,298			1,522,685
Computer equipment		285,048			285,048
Software		421,985			421,985

		7,560,109			8,633,142
Less accumulated depreciation and amortization		(6,649,128	)		(6,867,958	)

Property and equipment, net	$	910,981		$	1,765,184

Property and equipment depreciation and amortization expense for the years ended December 31, 2014 and 2013 was $678,713 and $970,489, respectively.

Commitments and Other Accrued Liabilities

12 Months Ended

Dec. 31, 2014

Commitments and Other Accrued Liabilities

3. Commitments and Other Accrued Liabilities

Operating Leases

The Company leases a facility in South San Francisco, California, under an operating lease agreement that extends to February 28, 2015. In connection with the lease agreement, a cash security deposit of $278,604 was made to the landlord and is classified as a short-term deposit. In February 2015, the Company entered into a new lease, see note 9 for further discussion.

The Company’s rental expense under its operating leases was $979,766 and $973,765 for the years ended December 31, 2014 and 2013, respectively.

Future minimum lease payments under all non-cancelable operating leases at December 31, 2014, were as follows:


Year ending December 31,
2015	$	94,830
Year ending December 31,
2015 (sublease)		341,682

Total future minimum lease payments	$	436,512

License Agreement Obligations

Under its technology license agreements to acquire certain technology rights, the Company has an obligation to pay minimum fees and then royalties based upon a percentage of any net sales of licensed products. License fees payable under the technology license agreements are $95,000 in 2013 and each year thereafter until royalties commence. The technology license agreements also provide for future payments to be made by the Company upon the achievement of development milestones or cumulative sales milestones. Pursuant to the license and collaboration agreement with ISU Abxis (see Note 6), the Company may be obligated to pay ISU Abxis up to $2.0 million in potential milestone payments. At December 31, 2014, no such milestones have been achieved.

Convertible Preferred Stock

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Convertible Preferred Stock

4.	Convertible Preferred Stock

In January 2015, the Company completed a Series F convertible preferred stock offering that generated $3.3 million , net of $74,000 of issuance costs. In the offering, the Company issued 2,623,650 shares of Series F convertible preferred stock at a price of $1.2706 per share. In conjunction with the Series F financing, the Company also amended the certificate of incorporation to increase the number of authorized shares of common stock to 160,000,000 shares.

All shares of convertible preferred stock have a liquidation preference in the event of a change of control event. In the event of a liquidation or winding up of the Company, holders of Series F convertible preferred stock are entitled to the liquidation preference of $6.3530 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, Series C and Series D and Series E convertible preferred stock. The holders of Series E convertible preferred stock have a liquidation preference that provides for a return of two (2) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock. The holders of Series D convertible preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock. Holders of Series CC convertible preferred stock, Series BB-1 convertible preferred stock, Series BB convertible preferred stock, and Series AA convertible preferred stock have a liquidation preference that provides for a dollar-for-dollar return of capital and then full participation on a pro rata basis as if converted to common stock. As the preferred stock is subject to a liquidation preference upon an event outside the control of the Company, the related amounts have been presented outside of stockholders’ deficit. The carrying value of preferred stock will be adjusted to redemption value if it becomes probable that a redemption will occur.

Redemption is not possible as the preferred stock was converted to common stock as of the Merger closing date of August 20, 2015.

Voting

Each share of convertible preferred stock is entitled to voting rights equivalent to the number of shares of common stock into which each share can be converted. Each share of common stock is entitled to one vote.

Conversion

Each share of Series F convertible preferred stock is convertible at the holder’s option at any time into ten shares common stock, subject to adjustment for anti-dilution. Each share of convertible preferred stock is convertible at the holder’s option at any time into common stock, subject to adjustment for anti-dilution. The conversion price for Series AA convertible preferred stock is $1.00 per share, for Series BB convertible preferred stock is $1.2706 per share, for Series BB-1 convertible preferred stock is $1.3843 per share, and for Series CC, Series D, Series E and Series F convertible preferred stock is $1.2706 per share. Conversion is automatic upon the closing of an underwritten public offering with an offering price of at least $3.8118 per share and aggregate gross proceeds of at least $40.0 million, or upon the written consent of holders of at least 66.67% of the then-outstanding convertible preferred stock.

Dividends

Holders of Series F convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series A, Series B, Series B-1, Series C and Series E convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors.

Holders of Series E convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series A, Series B, Series B-1, Series C, and Series D convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series D convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series A, Series B, Series B-1, and Series C convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series C convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series A, Series B, and Series B-1 convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series B and Series B-1 convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to the holders of Series A convertible preferred stock, at an annual rate of $0.101648 per share for the Series B convertible preferred stock and of $0.120432 per share for the Series B-1 convertible preferred stock, if and when declared by the board of directors. Holders of Series A convertible preferred stock are entitled to noncumulative dividends at an annual rate of $0.08 per share if and when declared by the board of directors. These dividends are to be paid in advance of any distributions to common stockholders. No dividends had been declared through June 30, 2015.

Liquidation

In the event of a liquidation or winding up of the Company, holders of Series F convertible preferred stock are entitled to the liquidation preference of $6.353 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, Series C, Series D and Series E convertible preferred stock. In the event of a liquidation or winding up of the Company, holders of Series E convertible preferred stock are entitled to the liquidation preference of $2.5412 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, Series C and Series D convertible preferred stock. In the event of a liquidation or winding up of the Company, holders of Series D convertible preferred stock are entitled to the liquidation preference of $6.353 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, and Series C convertible preferred stock. The holders of Series CC convertible preferred stock are entitled to the liquidation preference of $1.2706 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, and Series BB-1 convertible preferred stock. The holders of Series AA, Series BB, and Series BB-1 convertible preferred stock are then entitled to the liquidation preference of $1.00, $1.2706 and $1.5054, respectively, for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of common stock. After payment of these preferential amounts, the remaining assets of the Company shall be distributed among the holders of the convertible preferred stock and common stock pro rata based on the number of shares of common stock held (assuming conversion of the convertible preferred stock).

4. Stockholders’ Deficit and Convertible Preferred Stock

Convertible Preferred Stock and Warrants

On April 9, 2014, the Company completed a Series E convertible preferred stock offering that generated $5.0 million in gross proceeds. In the offering, Catalyst issued 983,778 Series E preferred stock warrant shares with a strike price equal to $1.2706 per share, with a corresponding term of five years from issuance as well as warrants to purchase a number of shares equal to 25% of Series E preferred shares purchased by the participants in the financing. The warrants have an exercise price of $1.2706 per share (as adjusted for stock splits, stock dividends, reclassification and the like) and expire on April 9, 2019.

The Company accounts for the preferred stock warrants in accordance with the guidance contained in ASC 815-40, whereby the warrants do not meet the criteria for equity treatment and must be recorded as a liability. Accordingly, the Company classifies the warrants as a liability at its fair value. The warrants are subject to remeasurement at each balance sheet date, with any change in fair value recognized as a component of other income (expense), net in the statements of operations.

The Company estimated the fair value of these warrants at the balance sheet date using the Black-Scholes option pricing model, based on the estimated market value of the underlying common stock at the valuation measurement date, the remaining contractual term of the warrant, risk-free interest rates and expected dividends on and expected volatility of the price of the underlying common stock. At issuance, the Preferred E Warrants were valued at $745,885. The Company revalued the warrants as of December 31, 2014 and the fair value of the Preferred E Warrants was $391,361.

The authorized, issued and outstanding shares of convertible preferred stock and liquidation preferences per share thereof as of December 31, 2014, were as follows:


	Shares Authorized		Shares Issued and Outstanding		Liquidation Preference Per Share
Series AA		7,327,166		7,327,166	$	1.0000
Series BB		23,104,618		23,104,618	$	1.2706
Series BB-1		5,978,477		5,978,477	$	1.5054
Series CC		46,429,980		46,429,980	$	1.2706
Series D		629,630		629,630	$	6.3530
Series E		5,000,000		3,935,140	$	2.5412

		88,469,871		87,405,011

All shares of preferred stock have a liquidation preference in the event of a change of control event. The holders of Series E preferred stock have a liquidation preference that provides for a return of two (2) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock. The holders of Series D preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock. Holders of Series CC preferred stock, Series BB-1 preferred stock, Series BB preferred stock, and Series AA preferred stock have a liquidation preference that provides for a dollar-for-dollar return of capital and then full participation on a pro rata basis as if converted to common stock. As the preferred stock is subject to a liquidation preference upon an event outside the control of the Company, the related amounts have been presented outside of stockholders’ deficit. The carrying value of preferred stock will be adjusted to redemption value if it becomes probable that a redemption will occur. Management does not believe that redemption is probable based on current business conditions.

Voting

Conversion

Each share of convertible preferred stock is convertible at the holder’s option at any time into common stock, subject to adjustment for anti-dilution. The conversion price for Series AA convertible preferred stock is $1.00 per share, for Series BB convertible preferred stock is $1.2706 per share, for Series BB-1 convertible preferred stock is $1.3843 per share, and for Series CC, Series D and Series E convertible preferred stock is $1.2706 per share. Conversion is automatic upon the closing of an underwritten public offering with an offering price of at least $3.8118 per share and aggregate gross proceeds of at least $40,000,000, or upon the written consent of holders of at least 66.67% of the then-outstanding convertible preferred stock.

Dividends

Holders of Series E convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series AA, Series BB, Series BB-1, Series CC, and Series D convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series D convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series AA, Series BB, Series BB-1, and Series CC convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series CC convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to holders of Series AA, Series BB, and Series BB-1 convertible preferred stock, at an annual rate of $0.101648 per share if and when declared by the board of directors. Holders of Series BB and Series BB-1 convertible preferred stock are entitled to noncumulative dividends, prior to the payment of any dividends to the holders of Series AA convertible preferred stock, at an annual rate of $0.101648 per share for the Series BB convertible preferred stock and of $0.120432 per share for the Series BB-1 convertible preferred stock, if and when declared by the board of directors. Holders of Series AA convertible preferred stock are entitled to noncumulative dividends at an annual rate of $0.08 per share if and when declared by the board of directors. These dividends are to be paid in advance of any distributions to common stockholders. No dividends had been declared through December 31, 2014.

Liquidation

In the event of a liquidation or winding up of the Company, holders of Series E convertible preferred stock are entitled to the liquidation preference of $2.5412 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, Series C and Series D convertible preferred stock. In the event of a liquidation or winding up of the Company, holders of Series D convertible preferred stock are entitled to the liquidation preference of $6.353 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, and Series C convertible preferred stock. The holders of Series CC convertible preferred stock are entitled to the liquidation preference of $1.2706 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, and Series BB-1 convertible preferred stock. The holders of Series AA, Series BB, and Series BB-1 convertible preferred stock are then entitled to the liquidation preference of $1.00, $1.2706 and $1.5054, respectively, for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of common stock. After payment of these preferential amounts, the remaining assets of the Company shall be distributed among the holders of the convertible preferred stock and common stock pro rata based on the number of shares of common stock held (assuming conversion of the convertible preferred stock).

2004 Incentive Stock Plan

The Company’s 2004 Stock Plan (the Plan) was adopted by the board of directors in January 2004. Pursuant to the Plan, options or stock purchase rights may be granted to employees and consultants of the Company. Options granted may be either incentive stock options or non-statutory stock options. Incentive stock options may be granted to employees with exercise prices of no less than the fair value of the common stock on the grant date, and non-statutory options may be granted to employees or consultants at exercise prices of no less than 85% of the fair value of the common stock on the grant date, as determined by the board of directors. Options vest as determined by the board of directors, generally over four years. The 2004 Incentive stock plan had a term of 10 years and expired in 2014. No more options can be issued under this plan.

However, on February 5, 2010, and March 17, 2009, the Company granted performance-based options to purchase 170,203 and 2,301,796 shares, respectively, to certain key members of management with the following vesting terms: 12.5% of the shares vest each year on the anniversary of the vesting commencement date subject to the optionee’s continued employment with the Company; an additional 12.5% of the total number of shares in each grant will be eligible for vesting each year on the anniversary of the vesting commencement date based upon the board of director’s determination of the achievement of Company goals or other achievements; and 100% of any unvested shares shall become vested immediately prior to the consummation of a change of control of the Company. Options granted under the Plan expire no more than ten years after the date of grant. Total expense associated with the performance-based options for the years December 31, 2014 and December 31, 2013, was $60,437 and $60,437 respectively.

The following table summarizes stock option activity under the Plan, including stock options granted to nonemployees, and related information:

2004 Incentive Stock Plan


			Outstanding Options
	Shares Available for Grant		Number of Shares Underlying Options Outstanding			Weighted- Average Exercise Price
Balances at December 31, 2013		315,141		6,435,868		$	0.34
Options exercised				(150,000	)		0.29
Options forfeited		59,685		(59,685	)		0.15
Stock repurchased		—		—			—

Balances at December 31, 2014		374,826		6,226,183		$	0.23

Since the 2004 Incentive Stock Plan expired the Company issued stock outside of the plan. The following table summarizes stock option activity for options issued outside of the plan. Stock options have only been granted to non-employees outside the plan

Out of Plan Options


			Outstanding Options
	Shares Available for Grant		Number of Shares Underlying Options Out of Plan Outstanding		Weighted- Average Exercise Price
Balances at December 31, 2013		—		—	$	—
Out of Plan Options granted				325,000		0.29
Options forfeited		—		—		—
Stock repurchased		—		—		—

Balances at December 31, 2014		—		325,000	$	0.29

At December 31, 2014, all of the outstanding options to purchase common stock of the Company were exercisable. The options are summarized in the following table:

2004 Incentive Stock Plan


Exercise Price Per Share	Number of Shares Underlying Options Outstanding		Number of Shares Underlying Options Vested		Weighted- Average Remaining Contractual Life
					(In Years)
$0.0500		30,000		30,000		0.6861
$0.0700		214,000		214,000		0.0700
$0.2800		2,642,815		2,642,815		5.2084
$0.3600		526,375		526,375		4.3173
$0.4000		826,206		769,605		6.1113
$0.4400		1,887,975		671,060		8.8634
$0.4800		98,812		82,268		7.4444

		6,226,183		4,936,123		5.5050

Out of plan options


Exercise Price Per Share	Number of Shares Underlying Options Outstanding		Number of Shares Underlying Options Vested		Weighted- Average Remaining Contractual Life
$0.2900		325,000		314,583		1.8300

At December 31, 2014, the total aggregate intrinsic value of options outstanding was $627,491. The weighted-average grant fair value of options granted during 2014 and 2013 was $0.23 and $0.29 per share, respectively. During the years ended December 31, 2014 and 2013, the total intrinsic value of options exercised based upon the difference between the exercise price and the estimated fair value of the shares as of the date of exercise was $0.06 and $0.00, respectively.

Options outstanding that have vested or are expected to vest as of December 31, 2014, are as follows:


	Number of Shares Underlying Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life		Aggregate Intrinsic Value
					(In Years)
Vested		5,109,350	$	0.34		5.453	$	84,378
Expected to Vest		748,782		0.34		5.453		84,378

Total		5,858,132	$	0.34		5.453	$	84,378

Options to purchase 0 and 1,500,370 shares of stock were granted to employees during 2014 and 2013, respectively. The compensation expense for the years ended December 31, 2014 and 2013, associated with stock option grants to employees was $0 and $175,713, respectively.

The estimated grant-date fair value-based measurements of the employee stock options were calculated using the Black-Scholes valuation model, based on the following weighted-average assumptions in the years ended December 31, 2014 and 2013:


	December 31,
	2014			2013
Expected term		5.14 years			5.98 years
Expected volatility		64.62	%		78.147	%
Risk-free interest rate		1.61	%		1.06	%
Expected dividend yield		0	%		0	%

Expected Term. Under the Company’s stock option plans, the expected term of options granted is determined using the simplified method which calculates expected term as the midpoint between the vesting date and the expiration date for each award.

Expected Volatility. Since the Company is a private entity with no historical data regarding the volatility of its common stock, the expected volatility used for 2014 and 2013 is based on the volatility of similar publicly traded entities, referred to as “guideline” companies.

Risk-Free Interest Rate. The risk-free rate is based on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term of the options.

Expected Dividend Yield. The Company has never declared or paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and, therefore, assumed an expected dividend yield of zero.

At December 31, 2014, the Company had employee stock-based compensation expense of $173,704 and at December 31, 2013 of $296,963 related to unvested stock awards not yet recognized, which is expected to be recognized over an estimated weighted-average period of 1.83 years.

Options Granted to Nonemployees

During 2014 and 2013, options to purchase 325,000 and 149,665 shares, respectively, of common stock were issued to consultants that vest over one to four years with a weighted-average exercise price of $0.29 and $0.44 per share, respectively. During the years ended December 31, 2014 and 2013, the Company recorded stock-based compensation expense attributable to these nonemployee stock awards of $70,710 and $61,670, respectively.

The estimated grant-date fair values of the nonemployee stock options were determined using the Black-Scholes valuation model and the following assumptions:


	Year Ended December 31,
	2014			2013
Risk-free interest rate		1.61	%		1.06	%
Expected volatility		64.62	%		78	%
Expected dividend yield		0	%		0	%
Weighted-average contractual term		5.14 years			5.98 years

Additional compensation of $180,992 will be recorded in future periods for the remaining unvested portions of the nonemployee option grants.

2012 Retention Plan

On December 5, 2012 the Company adopted a retention bonus plan for service providers, including employees, consultants and non-employee directors, to Catalyst. The plan provides for certain payments to be made to plan participants, up to a maximum of 10% of the total liquidation preference due to holders of Company preferred stock, in the event of a “Corporate Transaction” and corresponding liquidation preference payments made to holders of Company preferred stock.

In the plan, a Corporate Transaction is defined as: a merger in which the Company is not the surviving entity, a sale or disposition of substantially all of the assets of the Company, a complete liquidation or dissolution of the Company, or similar transaction. The retention bonus plan expires on December 5, 2022. No amounts have been accrued or paid through December 31, 2014.

Common Stock Warrants

In August 2004, the Company entered into three separate agreements with three individuals to obtain specified patent licenses related to the development of proteases as a therapeutic platform for oncology. In connection with these agreements, the Company issued warrants to purchase an aggregate of 15,000 shares of common stock of the Company at an exercise price of $0.05 per share. The warrants are exercisable upon the earlier of achieving certain patent-related milestones set forth in the agreement or on the seventh anniversary of the warrant agreement. The warrants were all exercisable and outstanding as of December 31, 2013. The warrants expired on August 9, 2014, unexercised.

In conjunction with the loan agreement that the Company entered into in March 2005 for equipment financing, the Company issued a warrant to the lender to purchase 33,750 shares of Series A convertible preferred stock of the Company at an exercise price of $1.00 per share. In February 2012, corresponding with a bridge loan financing, the warrant to purchase Series A convertible preferred stock was converted into a warrant to purchase Company common stock. The fair market value of the warrant at the time of conversion, $13,196, was reclassified as equity. Prior to the conversion the warrant was classified as a liability and at the end of each reporting period changes in the fair value of the warrant during the period are recorded in other income or expense. For the years ended December 31, 2014 and 2013, the Company recorded $0 of other income related to the changes in the fair value of the warrant. The warrant expired on March 3, 2015.

Income Taxes

12 Months Ended

Dec. 31, 2014

Income Taxes

5. Income Taxes

The Company did not record a provision (benefit) for income taxes for the years ended December 31, 2014 and 2013.

Significant components of the Company’s deferred tax assets as of December 31, 2014 and 2013 consist of the following (in thousands):


	Year Ended December 31,
	2014			2013
Deferred tax assets:
Accruals and reserves	$	1,382		$	858
Net operating loss carry forward		44,083			42,828
Tax credits		6,467			6,336
Fixed and intangible assets		43			18
Valuation Allowance		(51,975	)		(49,869	)

Total deferred tax assets:		—			171

Deferred tax liabilities:
Fixed Asset Basis Difference		—			(171	)

Total deferred tax liabilities:		—			—

Net Deferred	$	—		$	—

Reconciliations of the statutory federal income tax (benefit) to the Company’s effective tax for the years ended December 31, 2014 and 2013 are as follows (in thousands):


	Year Ended December 31,
	2014			2013
Tax (benefit) at statutory federal rate		34.00	%		34.00	%
State Tax (benefit)—net of federal benefit		-3.24	%		1.31	%
Permanent differences		1.83	%		-0.04	%
Credits		1.97	%		1.83	%
Change in Valuation Allowance		-34.25	%		-37.07	%
Other		-0.31	%		-0.19	%

Provision for Taxes		0.00	%		-0.16	%

Based on the available objective evidence, the Company does not believe it is more likely than not that the net deferred tax assets will be fully realizable. Accordingly, the Company has provided a full valuation allowance against its net deferred tax assets at December 31, 2014 and 2013.

At December 31, 2014 and 2013, the Company had approximately $112 million and $107 million federal net operating loss carry forwards (“NOL”), respectively, available to reduce future taxable income which, if unused, will begin to expire in 2025. At December 31, 2014 and 2013, the Company had approximately $104 million and $102 million state net operating loss carry forwards (“NOL”), respectively, available to reduce future taxable income which, if unused, will begin to expire in 2017. Of the above NOL amounts, $21,000 and $21,000, respectively, relate to windfall stock based compensation deductions which, when utilized, will be credited to equity.

The Company also had tax credit carry forwards available to offset future federal tax liabilities of approximately $5.4 million and $5.3 million for 2014 and 2013, respectively.

The Company had tax credit carry forwards available to offset future state tax liabilities of approximately $4.9 million and $4.8 million for 2014 and 2013, respectively. The federal tax credit, if unused, will begin to expire in 2024. The state tax credit does not expire.

Under Internal Revenue Code Section 382 and related provisions, the benefits from net operating loss and tax credit carry forwards may be limited in the event the Company has a cumulative ownership change of more than 50% over a three year period.

Accounting for Uncertainty in Income Taxes

The Company follows the provisions of the FASB’s guidance for accounting for uncertain tax positions. The guidance prescribes a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of any uncertain tax positions that have been taken or expected to be taken on a tax return.

It is the Company’s policy to include penalties and interest expense related to income taxes as a component of other expense and interest expense as necessary.

The unrecognized tax benefit was $2.57 million and $2.52 million at December 31, 2014 and December 31, 2013, respectively. The Company does not expect that its uncertain tax positions will materially change in the next twelve months. No liability related to uncertain tax positions is recorded on the financial statements related to uncertain tax positions. During the year ending December 31, 2014, the amount of unrecognized tax benefits increased due to additional research and development credits generated during the year. The reversal of the uncertain tax benefits would not impact the Company’s effective tax rate to the extent that the Company continues to maintain a full valuation allowance against its deferred tax assets.

The unrecognized tax benefit was as follows (in thousands):


Beginning Balance at January 1, 2013	$	2,409,043
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		107,817

Ending Balance at December 31, 2013	$	2,516,860

Beginning Balance at January 1, 2014	$	2,516,860
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		52,684

Ending Balance at December 31, 2014	$	2,569,544

The Company files income tax returns in the United States & California. The Company is not currently under examination by income tax authorities in federal, state or other jurisdictions. All tax returns will remain open for examination by the federal and state authorities from 2011 through 2013 from the date of utilization of any net operating loss or tax credits.

Collaborations

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Collaborations

6.	Collaborations

Pfizer

On August 20, 2013, the Company and Pfizer, Inc. (“Pfizer”) entered into an amendment to the Factor VIIa collaboration agreement whereby the companies agreed to provide specific mutual releases and covenants and modify certain milestone payment schedules in the agreement. Per the amendment, Pfizer agreed to make two non-refundable annual license maintenance payments to the Company, each $1,500,000, payable on August 1, 2014 and August 1, 2013. Contract revenue related to the agreement with Pfizer was $750,000 and $187,500 during the three months ended June 30, 2015 and 2014, respectively and $1,312,500 and $375,000 during the six months ended June 30, 2015 and 2014, respectively and reflects the amortization of the annual license maintenance payments received as amortized over the estimated expected performance period under the arrangement, which the Company originally estimated to end August 1, 2015.

On April 2, 2015, Pfizer notified the Company that it was exercising its right to terminate in its entirety the collaboration agreement. The termination became effective 60 days after the Company’s receipt of the termination notice. On June 1, 2015, the license and certain rights under the research and license agreement terminated and reverted back to the Company. Pfizer is in the process of transferring clinical trial data, regulatory documentation and related technology under the research and license agreement to the Company. The Company plans to continue clinical development of this product candidate. The Company revised the expected period of performance to end on June 1, 2015, which was the effective termination of all performance obligations of the Company under the research and license agreement. The deferred revenue balance related to the Pfizer collaboration was zero and $1,313,000 as of June 30, 2015 and December 31, 2014, respectively.

ISU Abxis

On September 16, 2013, the Company entered into a license and collaboration agreement with ISU Abxis, whereby the Company licensed its proprietary human Factor IX products to ISU Abxis for initial development in South Korea. Under the terms of the agreement, ISU Abxis is responsible for development and manufacturing of the licensed products through Phase 1 clinical trials. Until the completion of Phase 1 development, ISU Abxis also has a right of first refusal with respect to commercialization rights for the licensed products in South Korea. The Company has the sole rights and responsibility for worldwide development, manufacture and commercialization of Factor IX products after Phase 1 development, unless ISU Abxis has exercised its right of first refusal regarding commercialization rights in South Korea, in which case the Company’s rights are in the entire world excluding South Korea. ISU’s rights will also terminate in the event that the Company enters into a license agreement with another party to develop, manufacture and commercialize Factor IX products in at least two major market territories.

ISU Abxis paid the Company an up-front signing fee of $1,750,000 and is obligated to pay to the Company contingent milestone-based payments on the occurrence of certain defined development events, and reimbursement for a portion of the Company’s costs relating to intellectual property filings and maintenance thereof on products. The Company is obligated to pay ISU Abxis a percentage of all net profits it receives from collaboration products.

Contract revenue of $109,000 for each of the three months ended June 30, 2015 and 2014 and of $219,000 for each of the six months ended June 30, 2015 and 2014 reflected the amortization of the up-front fee over the estimated period of the Company’s performance obligations under the agreement, which was assessed to be four years beginning in September 2013 when the agreement was executed. The deferred revenue balance related to the ISU Abxis collaboration was $948,000 and $1,167,000 as of June 30, 2015, and December 31, 2014 respectively.

6. Collaborations

Pfizer

On June 29, 2009, Catalyst entered into a collaboration agreement with Wyeth, subsequently acquired by Pfizer, Catalyst and Pfizer collaborated on the development of novel human Factor VIIa products, and Catalyst granted Pfizer the exclusive rights to develop and commercialize the licensed products on a worldwide basis. Under the agreement, during a two-year collaboration period, Pfizer reimbursed Catalyst for certain of its costs incurred in the development of the licensed products, including FTE-based research payments, and Pfizer is obligated to continue to reimburse Catalyst for a portion of Catalyst’s costs relating to intellectual property filings and maintenance thereof on products developed in the collaboration. Pfizer is now responsible for all clinical development, manufacturing, and commercialization activities for the Factor VIIa products developed in the collaboration.

Pfizer paid Catalyst an up-front signing fee of $21,000,000, and is also obligated to make contingent cash payments to Catalyst based upon the achievement of predefined milestones. Contract revenue of $4,200,000 for each of the years ended December 31, 2011, and 2010, reflected the amortization of the up-front fee over the estimated period of the Company’s performance obligations under the agreement, which was assessed to be five years beginning in June 2009 when the agreement was executed. Further, as Pfizer terminated the research services under the agreement in June 2011 and the Company had no further substantive performance obligations to Pfizer, the Company recognized the remaining $12,576,667 of deferred revenue related to the up-front fee in 2011.

Additionally, during the years ended December 31, 2011, and 2010, the Company recognized $1,602,079 and $2,931,541, respectively, of FTE-based payments for research services as contract revenue as the related services were performed. In the years ended December 31, 2011, and 2010, the Company also recognized $7,000,000 and $4,000,000, respectively, of milestone and other contingent payments received in 2011, and 2010, respectively, upon the achievement of those milestones.

On August 20, 2013 Catalyst and Pfizer entered into an amendment to the Factor VIIa collaboration agreement whereby the companies agreed to provide specific mutual releases and covenants and modify certain milestone payment schedules in the agreement. Per the amendment, Pfizer agreed to make two non-refundable annual license maintenance payments to Catalyst, each $1,500,000, payable on August 1, 2013 and August 1, 2014. Contract revenue related to the agreement in the years 2014 and 2013 was $1,375,000 and $312,500, respectively and reflects the amortization of the annual license maintenance payments received as amortized over the estimated expected performance period for Catalyst per the amendment. The Company had deferred revenue remaining balance in the amount of $1,312,500 and $1,187,500 at December 31, 2014 and December 31, 2013, respectively, related to the Pfizer collaboration.

On April 2, 2015, Pfizer notified the Company that it was exercising its right to terminate in its entirety the June 29, 2009 research and license agreement between the Company and Wyeth. The termination becomes effective 60 days after the Company’s receipt of the termination notice. On June 1, 2015, the license and certain rights under the research and license agreement will terminate and revert back to the Company. Pfizer is in the process of transferring clinical trial data, regulatory documentation and related technology under the research and license agreement to the Company to enable the Company to continue the clinical development of this product candidate. The Company has revised the expected period of performance to end on June 1, 2015, which is the effective termination of all performance obligations of the Company under the research and license agreement. As a result, the $1.3 million of deferred revenue as of December 31, 2014 will be recognized ratably through June 1, 2015 rather than through August 31, 2015.

ISU Abxis

On September 16, 2013, Catalyst entered into a license and collaboration agreement with ISU Abxis, whereby Catalyst licensed its proprietary human Factor IX products to ISU Abxis for initial development in South Korea. Under the terms of the agreement, ISU Abxis is responsible for development and manufacturing of the licensed products through Phase 1 clinical trials. Until the completion of Phase 1 development, ISU Abxis also has a right of first refusal with respect to commercialization rights for the licensed products in South Korea. Catalyst has the sole rights and responsibility for worldwide development, manufacture and commercialization of Factor IX products after Phase 1 development, unless ISU Abxis has exercised its right of first refusal regarding commercialization rights in Korea, in which case Catalyst’s rights are in the entire world excluding South Korea. ISU’s rights will also terminate in the event that Catalyst enters into a license agreement with another party to develop, manufacture and commercialize Factor IX products in at least two major market territories.

ISU Abxis paid Catalyst an up-front signing fee of $1,750,000 and is obligated to pay to Catalyst contingent milestone-based payments on the occurrence of certain defined development events, and reimbursement for a portion of Catalyst’s costs relating to intellectual property filings and maintenance thereof on products. Catalyst is obligated to pay ISU Abxis a percentage of all net profits it receives from collaboration products.

Contract revenue of $437,500 and $145,833 for the years ended December 31, 2014 and December 31, 2013, respectively, reflected the amortization of the up-front fee over the estimated period of the Company’s performance obligations under the agreement, which was assessed to be four years beginning in September 2013 when the agreement was executed. The Company had deferred revenue remaining balance in the amount of $1,166,667 and $1,604,167 as of December 31, 2014 and December 31, 2013, respectively, related to the ISU Abxis collaboration.

Other Income

12 Months Ended

Dec. 31, 2014

Other Income

7. Other Income

On August 22, 2013 Catalyst entered into a sub-lease agreement to lease a portion of Catalyst’s leased facility in South San Francisco, CA. Under the sub-lease agreement the sublessee pays rent and a share of facility operating expenses monthly to Catalyst. The Company’s lease to the facility and the sub-lease arrangement both expired in February 2015 (See Note 9). In 2014 and 2013, the Company recorded $541,720 and $153,266, respectively, in other income related to sub-lease rent and operating expense reimbursement.

Litigation	12 Months Ended
Litigation	Dec. 31, 2014
Litigation	8. Litigation The Company is subject to various legal proceedings and claims arising in the ordinary course of business, which are related to industry-wide legal issues. Management believes that the ultimate resolution of these matters will not have a material adverse effect on the Company’s liquidity and results of operations.

Subsequent Events

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Subsequent events

8.	Subsequent events

On July 29, 2015, the Company completed a second closing of a Series F convertible preferred stock financing and issued 3,164,872 shares for gross cash proceeds of $4.0 million. In conjunction with the second closing of this Series F convertible preferred stock financing, the Company and the majority holders of the Notes amended the Notes such that the closing constituted a qualified financing and, accordingly, the total outstanding principal amount of the Notes of $1.9 million and all unpaid accrued interest of $30,000, were converted into 1,511,723 shares of Series F convertible preferred stock and 372,045 Series F preferred stock warrants were issued to the Notes holders in connection with the conversion of the Notes to Series F convertible preferred stock. All preferred stock and warrants were converted to common stock and warrants to purchase common stock.

9. Subsequent Events

The Company evaluated subsequent events for recognition or disclosure through May 22, 2015, the date the financial statements for the year ended December 31, 2014 were available to be issued.

Series F Financing

On January 22, 2015 the Company completed a Series F convertible preferred stock offering that generated $3.3M in gross proceeds. In the offering, the Company issued Series F convertible preferred stock at a price of $1.2706 per share. The Series F convertible preferred stock is convertible at a conversion price of $1.2706 per share. The Series F convertible preferred stock has a conversion rate of 10:1 such that each individual share of Series F convertible preferred stock is convertible into ten shares of common stock. In conjunction with the Series F financing, the Company amended the certificate of incorporation to increase the number of authorized shares. The Company has 160,000,000 shares of authorized common stock, $0.001 par value per share, and the authorized, issued, and outstanding shares of convertible preferred stock, $0.001 par value per share, and liquidation preferences per share thereof were as follows:


	Shares Authorized		Shares Issued and Outstanding		Liquidation Preference Per Share
Series AA		7,327,166		7,327,166	$	1.0000
Series BB		23,104,618		23,104,618	$	1.2706
Series BB-1		5,978,477		5,978,477	$	1.5054
Series CC		46,429,980		46,429,980	$	1.2706
Series D		629,630		629,630	$	6.3530
Series E		5,000,000		3,935,140	$	2.5412
Series F		4,000,000		2,623,650	$	6.3530

		92,469,871		90,028,661

All shares of preferred stock have a liquidation preference in the event of a change of control event. In the event of a liquidation or winding up of the Company, holders of Series F convertible preferred stock are entitled to the liquidation preference of $6.3530 for each such share of preferred stock, together with any declared but unpaid dividends, prior to the payment of any distributions to the holders of Series AA, Series BB, Series BB-1, Series C and Series D and Series E convertible preferred stock. The voting rights are equivalent to the voting rights of Series E convertible preferred stock. See Note 4.

New Lease

As of February 23, 2015 Catalyst signed a sublease in the same building that they have occupied since the current lease expired on February 28, 2015. The initial term of the sub-lease starts on March 1, 2015 and ends on August 31, 2015. The Sublease also has an extension option that would go through February 27, 2018. On March 1, 2015 the Company issued a letter of Credit in the amount of $56,947 held in the Company’s Money Market account to satisfy the security deposit requested by the sub lessor. The Company also issued a payment to sub lessor in the amount of $368,290 to prepay rent from March through August 31, 2015.

Merger Agreement

Targacept, Inc. (“Targacept”) and Catalyst Biosciences, jointly announced on March 5, 2015 that they had entered into a definitive agreement to merge the two companies. Subsequently, Targacept and Catalyst jointly amended the March 5, 2015 definitive merger agreement on May 6, 2015 and May 13, 2015. The combined entity, to be named Catalyst Biosciences, Inc., is intended to have combined capital including cash and cash equivalents of approximately $40.0 million at the closing of the transaction. There can be no assurances that the merger will be consummated.

The combined company will issue redeemable convertible notes with an aggregate principal amount of $37.0 million, which provides the potential for future capital investment in the combined company.

As part of the proposed transaction, the equityholders of Catalyst are expected to initially own approximately 58% of the combined company, and the operations of both companies will be combined. The initial ownership percentages are subject to adjustment based on Catalyst’s cash balance at closing. Targacept equity holders will retain approximately 42% of the combined company. Targacept stockholders will receive a dividend of an aggregate of $37.0 million in non-interest bearing convertible notes and approximately $19.0 million in cash. The notes will be convertible into the combined company’s common stock at any time within thirty months after closing at the noteholders’ discretion, at a conversion rate equal to $9.19, which represents 130% of the negotiated per-share value of the Company’s assets following the anticipated Pre-Closing Dividend, as adjusted to reflect the planned 7-for-1 reverse stock split described elsewhere in this proxy statement/prospectus/information statement. The combined company will establish an escrow fund of cash sufficient for repayment of any notes that are not converted to stock during the thirty months conversion period. If the redeemable convertible notes are fully converted, an additional $37.0 million held in escrow would be made available to the combined company within the thirty months following closing.

If the merger is consummated, Targacept’s name will be changed to Catalyst Biosciences, Inc., and Targacept will apply to change its ticker symbol on the NASDAQ Global Select Market to “CBIO”. Catalyst’s President and chief executive officer (CEO) will become the President and CEO of the combined company and the other Catalyst executive officers will assume their respective positions in the combined company, with select Targacept executives remaining involved on a transitional basis. The board of directors of the combined company will include four current board members of Catalyst and three from Targacept.

Merger (unaudited-subsequent to date of auditors report)

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Merger (unaudited-subsequent to date of auditors report)

9.	Merger Agreement

On August 20, 2015, the Company completed its business combination (“Merger”) with Targacept, Inc. (“Targacept”) in accordance with the terms of the Agreement and Plan of Merger, dated as of March 5, 2015, as amended on May 6 and May 13, 2015 (the “Merger Agreement”). Also on August 20, 2015, in connection with, and prior to the completion of, the Merger, Targacept effected a 7-for-1 reverse stock split of its common stock (the “Reverse Stock Split”) and changed its name to “Catalyst Biosciences, Inc.” Following the completion of the Merger, the business conducted by Targacept became primarily the business conducted by the Company, which is a biopharmaceutical company focused on creating and developing novel medicines to address serious medical conditions.

Immediately prior to and in connection with the Merger, each share of the Company’s preferred stock outstanding was converted into shares of the Company common stock at ratios determined in accordance with the Company’s certificate of incorporation then in effect. Under the terms of the Merger Agreement, at the effective time of the Merger, Targacept issued shares of its common stock to the Company stockholders, at an exchange rate of 0.0382 shares of common stock, after taking into account the Reverse Stock Split, in exchange for each share of the Company’s common stock outstanding immediately prior to the Merger. The exchange rate was calculated by a formula that was determined through arm’s-length negotiations between Targacept and the Company.

Immediately after the Merger, there were 11,416,984 shares of Catalyst’s common stock outstanding. Immediately after the Merger, the former Company equity holders beneficially owned approximately 59% of the common stock of Catalyst. In addition, former Company stockholders now holding approximately 53% of Catalyst’s outstanding common stock are party to lock-up agreements, pursuant to which such stockholders have agreed, except in limited circumstances, not to sell or transfer, or engage in swap or similar transactions with respect to, shares of Catalyst’s common stock, including, as applicable, shares received in the Merger and issuable upon exercise of certain warrants and options, for a period of 120 days following the completion of the Merger.

In addition, on August 19, 2015, prior to and in connection with the Merger, Targacept paid a dividend to the holders of Targacept’s common stock as of August 14, 2015, the record date for such dividend, of an aggregate cash amount of $19.5 million, which is approximately $0.5692 per share of Targacept’s stock as of the record date, or $3.984 per share after giving effect to the Reverse Stock Split, and non-interest bearing redeemable convertible notes in the aggregate principal amount of $37.0 million, which is approximately $1.08 per share of Targacept’s common stock as of the record date, or $7.56 per share after giving effect to the Reverse Stock Split (the “Pre-Closing Dividend”). The notes do not bear interest. The principal amounts under notes are convertible, at the option of each noteholder, into cash or into shares of Targacept’s common stock at a conversion rate of $9.19 per share (after taking into account the Reverse Stock Split), and are payable in cash, if not previously redeemed or converted, at maturity on January 20, 2018, the 30-month anniversary of the closing of the Merger.

10. Merger (unaudited-subsequent to date of auditors report)

On August 20, 2015, the Company completed its business combination with Targacept, Inc. These financial statements are of Old Catalyst and no effect has been given herein to the merger.

Nature of Operations and Basis of Presentation

6 Months Ended

Jun. 30, 2015

Nature of Operations and Basis of Presentation

1.	Nature of Operations and Basis of Presentation

Catalyst Biosciences, Inc. (the Company), was incorporated in the state of Delaware on August 8, 2002. The Company is a clinical-stage biotechnology company focused on engineering proteases as therapeutics for hemophilia, hemostasis, compliment-mediated diseases, and other unmet medical needs. The Company is located in South San Francisco, California and it operates in one segment.

The Company has an accumulated deficit of $120.9 million through June 30, 2015 and negative cash flows from operating activities and expects to continue to incur losses for the next several years. In August 2015, the Company completed the combined business with Targacept, Inc., which provided approximately $41.1 million in cash, cash equivalents and marketable securities (See Note 9). Management believes that the currently available resources, including the funds obtained will provide sufficient funds to enable the Company to meet its operating plan for at least the next twelve months. However, if anticipated operating results are not achieved in future periods, management believes that planned expenditures may need to be reduced in order to extend the time period over which the then-available resources would be able to fund operations.

The interim financial statements to which these Notes to Unaudited Interim Condensed Financial Statements relate are those of Catalyst Biosciences, Inc. (defined above as the “Company”) prior to the completion of the Merger as defined in Note 8 below. In connection with the Merger, the Company merged with Talos Merger Sub, Inc., a wholly-owned subsidiary of Targacept, Inc., with the Company surviving the merger and becoming a wholly owned subsidiary of Targacept, Inc. Immediately prior to the completion of the merger, the Company changed its name to Catalyst Bio, Inc., and Targacept, Inc. changed its name to Catalyst Biosciences, Inc.

For purposes of these Notes to Unaudited Interim Condensed Financial Statements, unless otherwise specifically referenced, (i) “Catalyst” refers to the registrant (formerly known as Targacept, Inc. prior to the completion of the Merger, and now known Catalyst Biosciences, Inc.) filing the Current Report on Form 8-K to which these Notes to Unaudited Interim Condensed Financial Statements are an Exhibit after the completion of the Merger, (ii) “Targacept” refers to the registrant prior to the completion of the Merger, and (iii) the “Company” refers to the entity, Catalyst Biosciences, Inc. the successor of which, as a result of the Merger, is Catalyst Bio, Inc., a wholly owned subsidiary of the registrant.

Convertible Notes - Related Parties

6 Months Ended

Jun. 30, 2015

Convertible Notes - Related Parties

3.	Convertible Notes – Related Parties

Convertible notes consisted of the following (in thousands):


	June 30, 2015			December 31, 2014
Convertible promissory notes	$	1,893		$	—
Accrued interest		11			—
Less: Debt discount		(446	)		—

Total convertible notes payable – related party	$	1,458		$	—

In May and June 2015, the Company issued and sold convertible promissory notes in a series of closings in the aggregate principal amount of $1.9 million to existing stockholders, together with warrants to purchase shares of either the Company’s Series E convertible preferred stock or the capital stock issued during the next financing. The convertible promissory notes accrue interest at a rate of 12% per annum and will mature one year from the date of issuance. If the Company, prior to the payment in full of the convertible promissory notes, issues and sells shares of preferred stock or common stock in a single transaction or series of related transactions for aggregate cash proceeds to the Company of at least $3.0 million (excluding any amount invested by cancellation of the indebtedness represented by the convertible promissory notes), the outstanding principal amount and unpaid accrued interest of the convertible promissory notes will be automatically converted into shares of the securities sold in such financing at a conversion price equal to the price per share paid by investors for such securities in the financing. Alternatively, if the Company, prior to the payment in full of the convertible promissory notes, issues and sells shares of preferred stock or common stock for aggregate cash proceeds to the Company of less than $3.0 million, the outstanding principal amount and unpaid accrued interest of the convertible promissory notes may be converted, at the option of the holder, into the same type of securities issued in such financing at a conversion price equal to the price per share paid by investors for such securities in the financing. In addition, at any time prior to repayment or conversion in full of the convertible promissory notes, the outstanding principal amount and unpaid accrued interest of the convertible promissory note may be converted, at the option of the holder, into shares of Series E convertible preferred stock at a conversion rate of $1.2706 per share.

In connection with the debt financing, the Company also issued and sold to each investor purchasing a convertible promissory note a warrant to purchase equity securities of the same type that the principal amount of the convertible promissory note issued to such investor converts into. The warrants are exercisable for up to a number of shares equal to the quotient of: (a) 25% multiplied by the principal amount of the convertible promissory note issued to such investor divided by (b) the stock purchase price equal to: (i) in the case the notes convert in connection with a financing the price per share of the securities paid by investors in such financing or (ii) in the case that the warrant shares are Series E convertible preferred stock, $1.2706 per share. The purchase price for each warrant was equal to 0.1% of the principal amount of the corresponding convertible promissory note. The exercise price for the warrant shares is equal to the stock purchase price.

The Company recorded the aggregate fair value of the warrants of $474,000 as a debt discount and warrant liability upon issuance of the convertible notes. The debt discount is accreted as additional interest expense over the term of the convertible promissory notes. The Company estimated the fair value of the warrants using an option-pricing valuation model with the following assumptions: expected term of five years, risk-free interest rate of 0.11% and 0.18%, expected volatility of 80.0% and a dividend yield of 0%.

For the three and six months ended June 30, 2015, the Company recognized interest expense of $39,000 related to the accrued interest and amortization of the debt discount within interest expense on the Company’s statement of operations and comprehensive loss.

As the holders of the convertible promissory notes each have an equity ownership in the Company, the convertible promissory notes are considered to be related-party transactions.

Stock Based Compensation

6 Months Ended

Jun. 30, 2015

Stock Based Compensation

5.	Stock Based Compensation

2004 Incentive Stock Plan

The 2004 Stock Plan (the Plan) expired in 2014 and no more options are available to be issued under the Plan. The following table summarizes stock option activity under the Plan, including stock options granted to non-employees, and related information :


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)
Outstanding — December 31, 2014		6,226,183		$	0.23		5.51
Options exercised		(100,000	)		0.13
Options canceled		(62,912	)		0.44

Outstanding — June 30, 2015		6,063,271		$	0.35		4.83

Exercisable— June 30, 2015		5,567,516		$	0.34		4.60

Vested and expected to vest — June 30, 2015		5,981,562		$	0.35		4.80

Since the Plan expired the Company has issued options for the purchase of common stock outside of the plan. The following table summarizes stock option activity for options issued outside of the Plan.


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)
Outstanding — December 31, 2014		325,000		$	0.29		9.15
Options granted		630,513			0.25
Options canceled		(25,000	)		0.29

Outstanding — June 30, 2015		930,513		$	0.27		9.38

Exercisable— June 30, 2015		395,473		$	0.29		8.87

Vested and expected to vest — June 30, 2015		847,674		$	0.27		9.34

During the six months ended June 30, 2015 and 2014, the total intrinsic value of options exercised based upon the difference between the exercise price and the estimated fair value of the shares as of the date of exercise was $16,000 and zero, respectively.

The weighted-average grant date fair value of options granted was $0.14 and $0.17 per share, respectively, during the three months ended June 30, 2015 and 2014, and $0.16 per share during the six months ended June 30, 2015 and 2014. The weighted-average grant date fair value of options vested was $0.24 and $0.26 per share, respectively, during the three months ended June 30, 2015 and 2014, and $0.25 and $0.24 per share, respectively, during the six months ended June 30, 2015 and 2014.

The estimated fair values of the stock options granted were determined using the Black-Scholes valuation model and the following assumptions:


	Three months ended June 30,						Six months ended June 30,
	2015			2014			2015			2014
Expected term		5.97			5.27			6.17			5.14
Expected volatility		67.35	%		66.70	%		67.19	%		64.62	%
Risk-free interest rate		1.68	%		1.73	%		1.63	%		1.61	%
Expected dividend yield		—			—			—			—

Total stock-based compensation recognized was as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Research and development	$	13	$	19	$	24	$	40
General and administrative		26		42		59		93

Total stock-based compensation	$	39	$	61	$	83	$	133

As of June 30, 2015, the Company had unrecognized employee stock-based compensation expense of $177,000, related to unvested stock awards, which is expected to be recognized over an estimated weighted-average period of 1.85 years.

Net Loss per Share

6 Months Ended

Jun. 30, 2015

Net Loss per Share

7.	Net Loss per Share

The following table sets forth the computation of the basic and diluted net loss per share during the three and six months ended June 30, 2014 and 2015 (in thousands, except share and per share data):


	Three Months Ended, June 30,						Six Months Ended June 30,
	2014			2015			2014			2015
Net loss, basic and diluted	$	(2,075	)	$	(1,724	)	$	(3,810	)	$	(4,582	)

Weighted-average number of shares used in computing net loss per share, basic and diluted		9,572,110			9,810,572			9,566,373			9,780,959

Net loss per share, basic and diluted	$	(0.22	)	$	(0.18	)	$	(0.40	)	$	(0.47	)

Since the Company was in a loss position for all periods presented, basic net loss per share is the same as diluted net loss per share for all periods as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:


	December 31,		June 30,
	2014		2015
Convertible preferred stock		87,405,011		90,028,661
Options to purchase common stock		6,551,183		6,993,784
Convertible preferred stock warrants		983,778		1,335,834
Convertible common stock warrants		33,750		33,750
Convertible promissory notes		—		1,496,735

Total		94,973,722		99,908,764

Summary of Significant Accounting Policies (Policies)

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Nature of Operations and Basis of Presentation

Nature of Operations and Basis of Presentation

Liquidity

Liquidity

Use of Estimates

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Such management estimates include the warrant for convertible preferred stock. The Company bases its estimates on various assumptions that the Company believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Operating Expenses

Operating Expenses

Cash and Cash Equivalents

Cash and Cash Equivalents

Cash and Cash Equivalents

Restricted Cash

Restricted Cash

Restricted Cash

At December 31, 2014 and 2013, the Company had restricted cash of $50,000 required as collateral for the Company’s corporate credit card.

Fair Value Measurement

Fair Value Measurements

•

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.

•


	Level 1		Level 2		Level 3			Total
As of June 30, 2015:
Money market funds	$	2,244	$	—	$	—		$	2,244
Warrant for convertible preferred stock liability		—		—		(270	)		(270	)

Total	$	2,244	$	—	$	(270	)	$	1,974


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,544	$	—	$	—		$	1,544
Warrant for convertible preferred stock liability		—		—		(391	)		(391	)

Total	$	1,544	$	—	$	(391	)	$	1,153

The following table present the activity for liabilities measured at estimated fair value using unobservable inputs for the six months ended June 30, 2015 (in thousands):


	Warrant for Convertible Stock
Beginning balance of warrant liability at December 31, 2014	$	391
Fair value of warrants issued during the period		474
Change in estimated fair value		(595	)

Ending balance of warrant liability at June 30, 2015	$	270

Fair Value Measurements

•

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.

•

The following table sets forth the Company’s assets that were measured at fair value and the level of the inputs used to value those assets and liabilities within the fair value hierarchy:


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,546,038	$	—	$	—		$	1,546,038
Warrant for convertible preferred stock		—		—		(391,361	)		(391,361	)

Total	$	1,546,038	$	—	$	(391,361	)	$	1,154,677


	Level 1		Level 2		Level 3			Total
As of December 31, 2013:
Money market funds	$	2,710,191	$	—	$	—		$	2,710,191

The following tables present the activity for liabilities measured at estimated fair value using unobservable inputs for the year ended December 31, 2014:


Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Warrant for Convertible Stock
Beginning balance at December 31, 2013	$	—
Issuance of warrants		745,885
Changes in estimated fair value		(354,524	)

Ending balance at December 31, 2014	$	391,361

Comprehensive Loss

Comprehensive Loss

Comprehensive Loss

Concentration of Credit Risk

Concentration of Credit Risk

Property and Equipment

Property and Equipment

Intangible Assets

Intangible Assets

Revenue Recognition

Revenue Recognition

Revenue Recognition

The Company enters into collaboration arrangements that may include the receipt of payments for up-front license fees, success-based milestone payments; full time equivalent (FTE) based payments for research services, and royalties on any future sales of commercialized products that result from the collaborations.

Collaborative agreement amounts received prior to satisfying revenue recognition criteria are recorded as deferred revenue in the accompanying balance sheets. Deferred revenue is recorded on our balance sheet as short-term or long-term based on our best estimate as to when such revenue will be recognized. Short-term deferred revenue consists of amounts that we expect to recognize as revenue in the next 12 months. Amounts that we expect will not be recognized prior to the next 12 months are classified as long-term deferred revenue.

Income Taxes

Income Taxes

It is the Company’s policy to include penalties and interest expense related to income taxes as a component of other expense and interest expense, respectively, as necessary.

Stock-Based Compensation

Stock-Based Compensation

Deferred Rent

Deferred Rent

New Accounting Pronouncement

New Accounting Pronouncement

Reclassification

Reclasssification

Certain reclassifications have been made to the 2013 financial statements to conform to the 2014 presentation.

Unaudited Interim Financial Information

Unaudited Interim Financial Information

Research and Development Expenses

Research and Development Expenses

Net Loss per Share

Net Loss per Share

Summary of Significant Accounting Policies (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2015

Dec. 31, 2014

Assets and Liabilities Measured at Fair Value


	Level 1		Level 2		Level 3			Total
As of June 30, 2015:
Money market funds	$	2,244	$	—	$	—		$	2,244
Warrant for convertible preferred stock liability		—		—		(270	)		(270	)

Total	$	2,244	$	—	$	(270	)	$	1,974


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,544	$	—	$	—		$	1,546
Warrant for convertible preferred stock liability		—		—		(391	)		(391	)

Total	$	1,544	$	—	$	(391	)	$	1,155

The following table sets forth the Company’s assets that were measured at fair value and the level of the inputs used to value those assets and liabilities within the fair value hierarchy:


	Level 1		Level 2		Level 3			Total
As of December 31, 2014:
Money market funds	$	1,546,038	$	—	$	—		$	1,546,038
Warrant for convertible preferred stock		—		—		(391,361	)		(391,361	)

Total	$	1,546,038	$	—	$	(391,361	)	$	1,154,677


	Level 1		Level 2		Level 3			Total
As of December 31, 2013:
Money market funds	$	2,710,191	$	—	$	—		$	2,710,191

Liabilities Measured at Estimated Fair Value

The following table present the activity for liabilities measured at estimated fair value using unobservable inputs for the six months ended June 30, 2015 (in thousands):


	Warrant for Convertible Stock
Beginning balance of warrant liability at December 31, 2014	$	391
Fair value of warrants issued during the period		474
Change in estimated fair value		(595	)

Ending balance of warrant liability at June 30, 2015	$	270

The following tables present the activity for liabilities measured at estimated fair value using unobservable inputs for the year ended December 31, 2014:


Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Warrant for Convertible Stock
Beginning balance at December 31, 2013	$	—
Issuance of warrants		745,885
Changes in estimated fair value		(354,524	)

Ending balance at December 31, 2014	$	391,361

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2014

Schdule of Property and equipment

Property and equipment consisted of the following:


	December 31,
	2014			2013
Laboratory and office equipment	$	5,026,560		$	6,092,206
Furniture		311,218			311,218
Leasehold improvements		1,515,298			1,522,685
Computer equipment		285,048			285,048
Software		421,985			421,985

		7,560,109			8,633,142
Less accumulated depreciation and amortization		(6,649,128	)		(6,867,958	)

Property and equipment, net	$	910,981		$	1,765,184

Commitments and Other Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2014

Expected Future Lease Payments Under All Operating Leases

Future minimum lease payments under all non-cancelable operating leases at December 31, 2014, were as follows:


Year ending December 31,
2015	$	94,830
Year ending December 31,
2015 (sublease)		341,682

Total future minimum lease payments	$	436,512

Subsequent Events (Tables)

12 Months Ended

Dec. 31, 2014

Authorized, Issued and Outstanding Shares of Convertible Preferred Stock and Liquidation Preferences

The authorized, issued and outstanding shares of convertible preferred stock and liquidation preferences per share thereof as of December 31, 2014, were as follows:


	Shares Authorized		Shares Issued and Outstanding		Liquidation Preference Per Share
Series AA		7,327,166		7,327,166	$	1.0000
Series BB		23,104,618		23,104,618	$	1.2706
Series BB-1		5,978,477		5,978,477	$	1.5054
Series CC		46,429,980		46,429,980	$	1.2706
Series D		629,630		629,630	$	6.3530
Series E		5,000,000		3,935,140	$	2.5412

		88,469,871		87,405,011

Subsequent Event

Authorized, Issued and Outstanding Shares of Convertible Preferred Stock and Liquidation Preferences

The Company has 160,000,000 shares of authorized common stock, $0.001 par value per share, and the authorized, issued, and outstanding shares of convertible preferred stock, $0.001 par value per share, and liquidation preferences per share thereof were as follows:


	Shares Authorized		Shares Issued and Outstanding		Liquidation Preference Per Share
Series AA		7,327,166		7,327,166	$	1.0000
Series BB		23,104,618		23,104,618	$	1.2706
Series BB-1		5,978,477		5,978,477	$	1.5054
Series CC		46,429,980		46,429,980	$	1.2706
Series D		629,630		629,630	$	6.3530
Series E		5,000,000		3,935,140	$	2.5412
Series F		4,000,000		2,623,650	$	6.3530

		92,469,871		90,028,661

Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2014

Stock Option Activity Plan, Including Stock Options Granted to Nonemployees, Related Information

The following table summarizes stock option activity under the Plan, including stock options granted to nonemployees, and related information:

2004 Incentive Stock Plan


			Outstanding Options
	Shares Available for Grant		Number of Shares Underlying Options Outstanding			Weighted- Average Exercise Price
Balances at December 31, 2013		315,141		6,435,868		$	0.34
Options exercised				(150,000	)		0.29
Options forfeited		59,685		(59,685	)		0.15
Stock repurchased		—		—			—

Balances at December 31, 2014		374,826		6,226,183		$	0.23

Outstanding Options to Purchase common Stock of Company Exercisable

outstanding options to purchase common stock of the Company were exercisable. The options are summarized in the following table:

2004 Incentive Stock Plan


Exercise Price Per Share	Number of Shares Underlying Options Outstanding		Number of Shares Underlying Options Vested		Weighted- Average Remaining Contractual Life
					(In Years)
$0.0500		30,000		30,000		0.6861
$0.0700		214,000		214,000		0.0700
$0.2800		2,642,815		2,642,815		5.2084
$0.3600		526,375		526,375		4.3173
$0.4000		826,206		769,605		6.1113
$0.4400		1,887,975		671,060		8.8634
$0.4800		98,812		82,268		7.4444

		6,226,183		4,936,123		5.5050

Out of plan options


Exercise Price Per Share	Number of Shares Underlying Options Outstanding		Number of Shares Underlying Options Vested		Weighted- Average Remaining Contractual Life
$0.2900		325,000		314,583		1.8300

Options Outstanding Vested or Expected to Vest

Options outstanding that have vested or are expected to vest as of December 31, 2014, are as follows:


	Number of Shares Underlying Options		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life		Aggregate Intrinsic Value
					(In Years)
Vested		5,109,350	$	0.34		5.453	$	84,378
Expected to Vest		748,782		0.34		5.453		84,378

Total		5,858,132	$	0.34		5.453	$	84,378

Employee [Member]

Estimated Grant-Date Fair Value-Based Measurements, Employee Stock Options


	December 31,
	2014			2013
Expected term		5.14 years			5.98 years
Expected volatility		64.62	%		78.147	%
Risk-free interest rate		1.61	%		1.06	%
Expected dividend yield		0	%		0	%

Non Employee [Member]

Estimated Grant-Date Fair Value-Based Measurements, Employee Stock Options

The estimated grant-date fair values of the nonemployee stock options were determined using the Black-Scholes valuation model and the following assumptions:


	Year Ended December 31,
	2014			2013
Risk-free interest rate		1.61	%		1.06	%
Expected volatility		64.62	%		78	%
Expected dividend yield		0	%		0	%
Weighted-average contractual term		5.14 years			5.98 years

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Components of the Company's Deferred Tax Assets (Liabilities)

Significant components of the Company’s deferred tax assets as of December 31, 2014 and 2013 consist of the following (in thousands):


	Year Ended December 31,
	2014			2013
Deferred tax assets:
Accruals and reserves	$	1,382		$	858
Net operating loss carry forward		44,083			42,828
Tax credits		6,467			6,336
Fixed and intangible assets		43			18
Valuation Allowance		(51,975	)		(49,869	)

Total deferred tax assets:		—			171

Deferred tax liabilities:
Fixed Asset Basis Difference		—			(171	)

Total deferred tax liabilities:		—			—

Net Deferred	$	—		$	—

Reconciliation of Federal Income Tax Rate to Company's Effective Tax Rate

Reconciliations of the statutory federal income tax (benefit) to the Company’s effective tax for the years ended December 31, 2014 and 2013 are as follows (in thousands):


	Year Ended December 31,
	2014			2013
Tax (benefit) at statutory federal rate		34.00	%		34.00	%
State Tax (benefit)—net of federal benefit		-3.24	%		1.31	%
Permanent differences		1.83	%		-0.04	%
Credits		1.97	%		1.83	%
Change in Valuation Allowance		-34.25	%		-37.07	%
Other		-0.31	%		-0.19	%

Provision for Taxes		0.00	%		-0.16	%

Unrecognized Tax Benefits

The unrecognized tax benefit was as follows (in thousands):


Beginning Balance at January 1, 2013	$	2,409,043
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		107,817

Ending Balance at December 31, 2013	$	2,516,860

Beginning Balance at January 1, 2014	$	2,516,860
Increase/(Decrease) of unrecognized tax benefits taken in prior years		—
Increase/(Decrease) of unrecognized tax benefits related to current year		52,684

Ending Balance at December 31, 2014	$	2,569,544

Convertible Notes - Related Parties (Tables)

6 Months Ended

Jun. 30, 2015

Convertible Notes

Convertible notes consisted of the following (in thousands):


	June 30, 2015			December 31, 2014
Convertible promissory notes	$	1,893		$	—
Accrued interest		11			—
Less: Debt discount		(446	)		—

Total convertible notes payable – related party	$	1,458		$	—

Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2015

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model

The estimated fair values of the stock options granted were determined using the Black-Scholes valuation model and the following assumptions:


	Three months ended June 30,						Six months ended June 30,
	2015			2014			2015			2014
Expected term		5.97			5.27			6.17			5.14
Expected volatility		67.35	%		66.70	%		67.19	%		64.62	%
Risk-free interest rate		1.68	%		1.73	%		1.63	%		1.61	%
Expected dividend yield		—			—			—			—

Summary of Stock-Based Compensation Recognized

Total stock-based compensation recognized was as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Research and development	$	13	$	19	$	24	$	40
General and administrative		26		42		59		93

Total stock-based compensation	$	39	$	61	$	83	$	133

Nonemployees Stock Option

Summary of Option Activity


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)
Outstanding — December 31, 2014		6,226,183		$	0.23		5.51
Options exercised		(100,000	)		0.13
Options canceled		(62,912	)		0.44

Outstanding — June 30, 2015		6,063,271		$	0.35		4.83

Exercisable— June 30, 2015		5,567,516		$	0.34		4.60

Vested and expected to vest — June 30, 2015		5,981,562		$	0.35		4.80

Stock Options Issued Outside of Plans

Summary of Option Activity

The following table summarizes stock option activity for options issued outside of the Plan.


	Number of Shares Underlying Outstanding Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)
Outstanding — December 31, 2014		325,000		$	0.29		9.15
Options granted		630,513			0.25
Options canceled		(25,000	)		0.29

Outstanding — June 30, 2015		930,513		$	0.27		9.38

Exercisable— June 30, 2015		395,473		$	0.29		8.87

Vested and expected to vest — June 30, 2015		847,674		$	0.27		9.34

Net Loss per Share (Tables)

6 Months Ended

Jun. 30, 2015

Basic and Diluted Net Loss Per Share


	Three Months Ended, June 30,						Six Months Ended June 30,
	2014			2015			2014			2015
Net loss, basic and diluted	$	(2,075	)	$	(1,724	)	$	(3,810	)	$	(4,582	)

Weighted-average number of shares used in computing net loss per share, basic and diluted		9,572,110			9,810,572			9,566,373			9,780,959

Net loss per share, basic and diluted	$	(0.22	)	$	(0.18	)	$	(0.40	)	$	(0.47	)

Anti-dilutive Security not Included In Diluted per Share Calculations

Potentially dilutive securities that were not included in the diluted per share calculations because they would be anti-dilutive were as follows:


	December 31,		June 30,
	2014		2015
Convertible preferred stock		87,405,011		90,028,661
Options to purchase common stock		6,551,183		6,993,784
Convertible preferred stock warrants		983,778		1,335,834
Convertible common stock warrants		33,750		33,750
Convertible promissory notes		—		1,496,735

Total		94,973,722		99,908,764

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2009
Significant Accounting Policies [Line Items]
Cumulative net losses	$ (120,857,000)		$ (120,857,000)		$ (116,274,661)	$ (109,661,406)
Operating expenses	3,060,000	$ 2,507,000	6,765,000	$ 4,667,000	9,322,204	10,643,258
Restricted cash	107,000		107,000		50,000	50,000
Accounts receivable	87,000		87,000		95,063	96,092
Patent rights							$ 70,567
Short-term deferred revenue	438,000		438,000		1,750,000	1,187,500
Long-term deferred revenue	510,000		510,000		729,167	1,604,167
Uncertain tax positions					$ 0	0
Number of open tax years					3 years
Reduction to research and development expense	$ 87,000,000	$ 82,000,000	$ 469,000,000	$ 195,000,000
Minimum
Significant Accounting Policies [Line Items]
Open tax year					2011
Maximum
Significant Accounting Policies [Line Items]
Open tax year					2014
Patents
Significant Accounting Policies [Line Items]
Intangible assets amortization period					20 years, or life of the patent whichever is shorter
Amortization of intangible assets					$ 883	3,528
Accumulated amortization intangible assets					17,348
Intangible assets written off to amortization expense					$ 53,219
Computer equipment
Significant Accounting Policies [Line Items]
Estimated useful lives					3 years
Laboratory and office equipment \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives					3 years
Laboratory and office equipment \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives					7 years
Furniture \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives					3 years
Furniture \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives					7 years
Leasehold improvements \| Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives					3 years
Leasehold improvements \| Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives					7 years
Pfizer Inc
Significant Accounting Policies [Line Items]
Accounts receivable					$ 79,857
ISU Abxis
Significant Accounting Policies [Line Items]
Accounts receivable					15,206
Third Parties
Significant Accounting Policies [Line Items]
Operating expenses					$ 381,465	$ 175,713

Assets and Liabilities Measured at Fair Value (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 1,974,000	$ 1,154,677
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	2,244,000	1,546,038	$ 2,710,191
Warrant For Convertible Preferred Stock Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant for convertible preferred stock liability	(270,000)	(391,361)
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	2,244,000	1,546,038
Fair Value, Inputs, Level 1 \| Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	2,244,000	1,546,038	$ 2,710,191
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	(270,000)	(391,361)
Fair Value, Inputs, Level 3 \| Warrant For Convertible Preferred Stock Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrant for convertible preferred stock liability	$ (270,000)	$ (391,361)

Liabilities Measured at Estimated Fair Value (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in estimated fair value	$ 516,000	$ 595,000	$ 354,524
Warrant For Convertible Stock
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance of warrant liability		391,361
Fair value of warrants issued during the period	474,000	474,000	745,885
Change in estimated fair value		(595,000)	(354,524)
Ending balance of warrant liability	$ 270,000	$ 270,000	$ 391,361

Property and Equipment (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		$ 7,560,109	$ 8,633,142
Less accumulated depreciation and amortization		(6,649,128)	(6,867,958)
Property and equipment, net	$ 653,000	910,981	1,765,184
Laboratory and office equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		5,026,560	6,092,206
Furniture
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		311,218	311,218
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		1,515,298	1,522,685
Computer equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		285,048	285,048
Software
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross		$ 421,985	$ 421,985

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 678,713	$ 970,489

Commitments and Other Accrued Liabilities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Line Items]
Operating lease agreement end date	Feb. 28, 2015
Cash security deposit	$ 278,604
Operating lease rent expense	979,766	$ 973,765
License fees payable		$ 95,000
ISU Abxis \| Maximum
Commitments and Contingencies Disclosure [Line Items]
Potential milestone payments	$ 2,000,000

Expected Future Lease Payments Under Operating Leases (Detail)	Dec. 31, 2014 USD ($)
Capital and Operating Leased Assets [Line Items]
Year ending December 31, 2015	$ 94,830
Year ending December 31, 2015 (sublease)	341,682
Total future minimum lease payments	$ 436,512

Convertible Preferred Stock - Additional Information (Detail) - USD ($)		1 Months Ended	6 Months Ended		12 Months Ended
	Apr. 09, 2014	Jan. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Convertible preferred stock, principal offer amount			$ 3,260,000	$ 4,983,000	$ 4,981,985	$ 5,742,060
Liquidation preference description			The holders of Series D convertible preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.
Warrant liability	$ 745,885		$ 270,000		$ 391,361
Convertible preferred stock voting rights			Each share of common stock is entitled to one vote.		Each share of common stock is entitled to one vote.
Common stock, shares authorized			160,000,000		110,000,000	104,000,000
IPO \| Minimum
Debt Instrument [Line Items]
Convertible preferred stock, shares issued per share value			$ 3.8118		$ 3.8118
Gross Proceeds			$ 40,000,000		$ 40,000,000
Series E Convertible Preferred Stock
Debt Instrument [Line Items]
Convertible preferred stock, principal offer amount	$ 5,000,000
Convertible preferred stock, shares issued	983,778
Convertible preferred stock, shares issued per share value	$ 1.2706
Liquidation preference description	In the offering, Catalyst issued 983,778 Series E preferred stock warrant shares with a strike price equal to $1.2706 per share, with a corresponding term of five years from issuance as well as warrants to purchase a number of shares equal to 25% of Series E preferred shares purchased by the participants in the financing.		The holders of Series E convertible preferred stock have a liquidation preference that provides for a return of two (2) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.		The holders of Series E preferred stock have a liquidation preference that provides for a return of two (2) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.
Conversion Price Per Share			$ 1.2706		$ 1.2706
Convertible preferred stock, annual dividend rate			0.101648		0.101648
Liquidation Preference Per Share			$ 2.5412		$ 2.5412
Series F Convertible Preferred Stock
Debt Instrument [Line Items]
Convertible preferred stock, shares issued		2,623,650
Convertible preferred stock, shares issued per share value		$ 1.2706
Liquidation preference description			Each share of Series F convertible preferred stock is convertible at the holder's option at any time into ten shares common stock, subject to adjustment for anti-dilution. Each share of convertible preferred stock is convertible at the holder's option at any time into common stock, subject to adjustment for anti-dilution		Each share of Series F convertible preferred stock is convertible at the holder's option at any time into ten shares common stock, subject to adjustment for anti-dilution. Each share of convertible preferred stock is convertible at the holder's option at any time into common stock, subject to adjustment for anti-dilution.
Conversion Price Per Share			$ 1.2706
Convertible preferred stock, annual dividend rate			0.101648
Liquidation Preference Per Share			6.353		$ 6.353
Convertible preferred stock, principal offer amount		$ 3,300,000
Convertible preferred stock, issuance cost		$ 74,000
Common stock, shares authorized		160,000,000
Preferred stock, liquidation preference per share			$ 6.3530
Series D Convertible Preferred Stock
Debt Instrument [Line Items]
Liquidation preference description			The holders of Series D convertible preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.		The holders of Series D preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.
Conversion Price Per Share			$ 1.2706		$ 1.2706
Convertible preferred stock, annual dividend rate			0.101648		0.101648
Liquidation Preference Per Share			6.353		6.353
Series AA Convertible Preferred Stock
Debt Instrument [Line Items]
Conversion Price Per Share			1.00		1.00
Convertible preferred stock, annual dividend rate			0.08		0.08
Liquidation Preference Per Share			1.00		1.00
Series BB Convertible Preferred Stock
Debt Instrument [Line Items]
Conversion Price Per Share			1.2706		1.2706
Convertible preferred stock, annual dividend rate			0.101648		0.101648
Liquidation Preference Per Share			1.2706		1.2706
Series BB-1 Convertible Preferred Stock
Debt Instrument [Line Items]
Conversion Price Per Share			1.3843		1.3843
Convertible preferred stock, annual dividend rate			0.120432		0.120432
Liquidation Preference Per Share			1.5054		1.5054
Series CC Convertible Preferred Stock
Debt Instrument [Line Items]
Convertible preferred stock, shares issued per share value						$ 1.2706
Conversion Price Per Share			1.2706		1.2706
Convertible preferred stock, annual dividend rate			0.101648		0.101648
Liquidation Preference Per Share			$ 1.2706		$ 1.2706

Schedule of Series of Shares Authorized, Issued, Outstanding and Liquidation Preference Per Share (Detail) - $ / shares	Jun. 30, 2015	Jan. 22, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Shares Authorized			88,469,871
Shares Issued			87,405,011
Shares Outstanding			87,405,011
Subsequent Event
Class of Stock [Line Items]
Shares Authorized		92,469,871
Shares Issued		90,028,661
Shares Outstanding		90,028,661
Series AA Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	7,327,166		7,327,166	7,327,166
Shares Issued	7,327,166		7,327,166	7,327,166
Shares Outstanding	7,327,166		7,327,166	7,327,166
Liquidation Preference Per Share	$ 1.00		$ 1.00
Series AA Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		7,327,166
Shares Issued		7,327,166
Shares Outstanding		7,327,166
Liquidation Preference Per Share		$ 1.0000
Series BB Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	23,104,618		23,104,618	23,104,618
Shares Issued	23,104,618		23,104,618	23,104,618
Shares Outstanding	23,104,618		23,104,618	23,104,618
Liquidation Preference Per Share	$ 1.2706		$ 1.2706
Series BB Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		23,104,618
Shares Issued		23,104,618
Shares Outstanding		23,104,618
Liquidation Preference Per Share		$ 1.2706
Series BB-1 Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	5,978,477		5,978,477	5,978,477
Shares Issued	5,978,477		5,978,477	5,978,477
Shares Outstanding	5,978,477		5,978,477	5,978,477
Liquidation Preference Per Share	$ 1.5054		$ 1.5054
Series BB-1 Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		5,978,477
Shares Issued		5,978,477
Shares Outstanding		5,978,477
Liquidation Preference Per Share		$ 1.5054
Series CC Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	46,429,980		46,429,980	46,429,980
Shares Issued	46,429,980		46,429,980	46,429,980
Shares Outstanding	46,429,980		46,429,980	46,429,980
Liquidation Preference Per Share	$ 1.2706		$ 1.2706
Series CC Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		46,429,980
Shares Issued		46,429,980
Shares Outstanding		46,429,980
Liquidation Preference Per Share		$ 1.2706
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	629,630		629,630	629,630
Shares Issued	629,630		629,630	629,630
Shares Outstanding	629,630		629,630	629,630
Liquidation Preference Per Share	$ 6.353		$ 6.353
Series D Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		629,630
Shares Issued		629,630
Shares Outstanding		629,630
Liquidation Preference Per Share		$ 6.3530
Series E Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	4,918,918		5,000,000
Shares Issued	3,935,140		3,935,140
Shares Outstanding	3,935,140		3,935,140
Liquidation Preference Per Share	$ 2.5412		$ 2.5412
Series E Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		5,000,000
Shares Issued		3,935,140
Shares Outstanding		3,935,140
Liquidation Preference Per Share		$ 2.5412
Series F Convertible Preferred Stock
Class of Stock [Line Items]
Shares Authorized	4,000,000		0
Shares Issued	2,623,650		0
Shares Outstanding	2,623,650		0
Liquidation Preference Per Share	$ 6.353		$ 6.353
Series F Convertible Preferred Stock \| Subsequent Event
Class of Stock [Line Items]
Shares Authorized		4,000,000
Shares Issued		2,623,650
Shares Outstanding		2,623,650
Liquidation Preference Per Share		$ 6.3530

2004 Incentive Stock Plan - Additional Information (Detail) - USD ($)			3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 05, 2010	Mar. 17, 2009	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense					$ 83,000	$ 133,000	$ 244,413	$ 297,820
2004 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, Description							Incentive stock options may be granted to employees with exercise prices of no less than the fair value of the common stock on the grant date, and non-statutory options may be granted to employees or consultants at exercise prices of no less than 85% of the fair value of the common stock on the grant date, as determined by the board of directors.
Award Vesting Period							4 years
Award, Expiration Period							10 years
Intrinsic value of options outstanding					$ 16,000	$ 0	$ 627,491
Weighted average grant date fair value			$ 0.14	$ 0.17	$ 0.16	$ 0.16	$ 0.23	$ 0.29
Weighted average grant Intrinsic value							$ 0.06	$ 0.00
2004 Stock Plan \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, Expiration Period							10 years
Options, Grants in Period	170,203	2,301,796
Vesting Rights, Percentage							12.50%
Award Vesting Rights							certain key members of management with the following vesting terms: 12.5% of the shares vest each year on the anniversary of the vesting commencement date subject to the optionee’s continued employment with the Company; an additional 12.5% of the total number of shares in each grant will be eligible for vesting each year on the anniversary of the vesting commencement date based upon the board of director’s determination of the achievement of Company goals or other achievements; and 100% of any unvested shares shall become vested immediately prior to the consummation of a change of control of the Company. Options granted under the Plan expire no more than ten years after the date of grant
Stock-based compensation expense							$ 60,437	$ 60,437
2004 Stock Plan \| Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Grants in Period							0	1,500,370
Stock-based compensation expense							$ 0	$ 175,713
Expected dividend yield							0.00%	0.00%
Compensation Cost Not yet Recognized, Period for Recognition					1 year 10 months 6 days		1 year 9 months 29 days
Compensation Not yet Recognized, Stock Options			$ 177,000		$ 177,000		$ 173,704	$ 296,963

Summary of Option Activity (Detail) - $ / shares	6 Months Ended	12 Months Ended
Summary of Option Activity (Detail) - $ / shares	Jun. 30, 2015	Dec. 31, 2014
Weighted Average Remaining Contractual Term
Outstanding - December 31, 2014		5 years 5 months 13 days
Non Employee Stock Option
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Beginning Balance	$ 0.29	$ 0.44
Weighted Average Exercise Price Per Share, Ending Balance		$ 0.29
2004 Stock Plan
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	6,226,183
Number of Shares Underlying Outstanding Options, Ending Balance		6,226,183
Weighted Average Remaining Contractual Term
Exercisable - June 30, 2015		5 years 6 months 2 days
2004 Stock Plan \| Non Employee Stock Option
Shares Available for Grant
Balances at December 31, 2013	374,826	315,141
Options forfeited		59,685
Stock repurchased		0
Balances at December 31, 2014		374,826
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	6,226,183	6,435,868
Number of Shares Underlying Outstanding Options, Options exercised	(100,000)	(150,000)
Number of Shares Underlying Outstanding Options, Options canceled	(62,912)	(59,685)
Stock repurchased		0
Number of Shares Underlying Outstanding Options, Ending Balance	6,063,271	6,226,183
Number of Shares Underlying Outstanding Options, Exercisable - June 30, 2015	5,567,516
Number of Shares Underlying Outstanding Options, Vested and expected to vest - June 30, 2015	5,981,562
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Beginning Balance	$ 0.23	$ 0.34
Options exercised	0.13	0.29
Options canceled	0.44	$ 0.15
Stock repurchased		0
Weighted Average Exercise Price Per Share, Ending Balance	0.35	$ 0.23
Exercisable - June 30, 2015	0.34
Vested and expected to vest - June 30, 2015	$ 0.35
Weighted Average Remaining Contractual Term
Outstanding - December 31, 2014	4 years 9 months 29 days	5 years 6 months 4 days
Exercisable - June 30, 2015	4 years 7 months 6 days
Vested and expected to vest - June 30, 2015	4 years 9 months 18 days
2004 Stock Plan \| Stock Options Issued Outside of Plans
Shares Available for Grant
Stock repurchased		0
Number of Shares Underlying Outstanding Options
Number of Shares Underlying Outstanding Options, Beginning Balance	325,000
Number of Shares Underlying Outstanding Options, Options granted	630,513	325,000
Number of Shares Underlying Outstanding Options, Options canceled	(25,000)
Stock repurchased		0
Number of Shares Underlying Outstanding Options, Ending Balance	930,513	325,000
Number of Shares Underlying Outstanding Options, Vested and expected to vest - June 30, 2015	847,674
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Beginning Balance	$ 0.29
Options exercised	0.25	$ 0.29
Options canceled	0.29
Stock repurchased		0
Stock repurchased		$ 0
Weighted Average Exercise Price Per Share, Ending Balance	0.27	$ 0.29
Vested and expected to vest - June 30, 2015	$ 0.27
Weighted Average Remaining Contractual Term
Outstanding - December 31, 2014	9 years 4 months 17 days	9 years 1 month 24 days
Exercisable - June 30, 2015	8 years 10 months 13 days	1 year 9 months 29 days
Vested and expected to vest - June 30, 2015	9 years 4 months 2 days

Summary of Options to Purchase Common Stock By Exercise Price (Detail) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Underlying Options Vested		5,109,350
2004 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Underlying Options Outstanding		6,226,183
Number of Shares Underlying Options Vested		4,936,123
Weighted- Average Remaining Contractual		5 years 6 months 2 days
2004 Stock Plan \| Stock Options Issued Outside of Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.2900
Number of Shares Underlying Options Outstanding	930,513	325,000
Number of Shares Underlying Options Vested		314,583
Weighted- Average Remaining Contractual	8 years 10 months 13 days	1 year 9 months 29 days
2004 Stock Plan \| 0.0500
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.0500
Number of Shares Underlying Options Outstanding		30,000
Number of Shares Underlying Options Vested		30,000
Weighted- Average Remaining Contractual		8 months 7 days
2004 Stock Plan \| 0.0700
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.0700
Number of Shares Underlying Options Outstanding		214,000
Number of Shares Underlying Options Vested		214,000
Weighted- Average Remaining Contractual		8 months 7 days
2004 Stock Plan \| 0.2800
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.2800
Number of Shares Underlying Options Outstanding		2,642,815
Number of Shares Underlying Options Vested		2,642,815
Weighted- Average Remaining Contractual		5 years 2 months 15 days
2004 Stock Plan \| 0.3600
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.3600
Number of Shares Underlying Options Outstanding		526,375
Number of Shares Underlying Options Vested		526,375
Weighted- Average Remaining Contractual		4 years 3 months 25 days
2004 Stock Plan \| 0.4000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.4000
Number of Shares Underlying Options Outstanding		826,206
Number of Shares Underlying Options Vested		769,605
Weighted- Average Remaining Contractual		6 years 1 month 10 days
2004 Stock Plan \| 0.4400
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.4400
Number of Shares Underlying Options Outstanding		1,887,975
Number of Shares Underlying Options Vested		671,060
Weighted- Average Remaining Contractual		8 years 10 months 11 days
2004 Stock Plan \| 0.4800
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price Per Share		$ 0.4800
Number of Shares Underlying Options Outstanding		98,812
Number of Shares Underlying Options Vested		82,268
Weighted- Average Remaining Contractual		7 years 5 months 10 days

Summary of Options Outstanding Vested And Expected to Vest (Detail)	12 Months Ended
	Dec. 31, 2014 USD ($) $ / shares shares
Shares
Vested \| shares	5,109,350
Expected to Vest \| shares	748,782
Total \| shares	5,858,132
Weighted Average Exercise Price Per Share
Vested \| $ / shares	$ 0.34
Expected to Vest \| $ / shares	0.34
Total \| $ / shares	$ 0.34
Vested	5 years 5 months 13 days
Expected to Vest	5 years 5 months 13 days
Total	5 years 5 months 13 days
Aggregate Intrinsic Value
Vested \| $	$ 84,378
Expected to Vest \| $	84,378
Total \| $	$ 84,378

Fair Values of Stock Options Estimated Using Black-Scholes Valuation Model (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term	5 years 11 months 19 days	5 years 3 months 7 days	6 years 2 months 1 day	5 years 1 month 21 days
Expected volatility	67.35%	66.70%	67.19%	64.62%
Risk-free interest rate	1.68%	1.73%	1.63%	1.61%
Non Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term					5 years 1 month 21 days	5 years 1 month 21 days
Expected volatility					64.62%	78.00%
Risk-free interest rate					1.61%	1.06%
Expected dividend yield					0.00%	0.00%
2004 Stock Plan \| Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Black Scholes Method Used [Line Items]
Expected term					5 years 1 month 21 days	5 years 1 month 21 days
Expected volatility					64.62%	78.147%
Risk-free interest rate					1.61%	1.06%
Expected dividend yield					0.00%	0.00%

Options Granted to Nonemployees - Additional Information (Detail) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 83,000	$ 133,000	$ 244,413	$ 297,820
Non Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Grants in Period			325,000	149,665
Options, Outstanding, Weighted Average Exercise Price			$ 0.29	$ 0.44
Stock-based compensation expense			$ 70,710	$ 61,670
Non Employee Stock Option \| Scenario, Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 180,992
Non Employee Stock Option \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period			1 year
Non Employee Stock Option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award Vesting Period			4 years

2012 Retention Plan - Additional Information (Detail)		6 Months Ended
2012 Retention Plan - Additional Information (Detail)	Dec. 05, 2012	Jun. 30, 2015
Debt Instrument [Line Items]
Liquidation preference description		The holders of Series D convertible preferred stock have a liquidation preference that provides for a return of five (5) times the amount of original investment and then full participation on a pro rata basis as if converted to common stock.
2012 Retention Plan \| Maximum
Debt Instrument [Line Items]
Liquidation preference description	The plan provides for certain payments to be made to plan participants, up to a maximum of 10% of the total liquidation preference due to holders of Company preferred stock, in the event of a "Corporate Transaction" and corresponding liquidation preference payments made to holders of Company preferred stock.

- Definition

Description of the type or class of security that is classified as temporary equity, including its redemption features (for example, sinking fund, at option of holders, out of future earnings), conversion features, and the rights of holders, if any, in the event of default, including the effect, if any, on junior securities in the event a required dividend, sinking fund, or other redemption payment(s) is not paid. Include also a description of stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References + Details

Common Stock Warrants - Additional Information (Detail)	1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
Common Stock Warrants - Additional Information (Detail)	Aug. 31, 2004 USD ($) Agreement $ / shares	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2015 $ / shares shares	Feb. 29, 2012 shares
Debt Instrument [Line Items]
Other Income		$ 135,000	$ 96,000	$ 263,000	$ 541,925	$ 153,613
Series AA Convertible Preferred Stock
Debt Instrument [Line Items]
Common stock, exercise price \| $ / shares							$ 1.00
Issued warrants to purchase \| shares							33,750
Common Stock Warrant
Debt Instrument [Line Items]
Issued warrants to purchase	$ 15,000
Common stock, exercise price \| $ / shares	$ 0.05
Number Of Patent License Agreement \| Agreement	3
Warrants Expiration Date	Aug. 09, 2014				Mar. 03, 2015
Number Of Patent License Agreement \| shares								13,196
Other Income					$ 0	$ 0

Components of Company's Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Accruals and reserves	$ 1,382	$ 858
Net operating loss carry forward	44,083	42,828
Tax credits	6,467	6,336
Fixed and intangible assets	43	18
Valuation Allowance	(51,975)	(49,869)
Total deferred tax assets:		171
Deferred tax liabilities:
Fixed Asset Basis Difference		(171)
Total deferred tax liabilities:	0	0
Net Deferred	$ 0	$ 0

Reconciliation of Statutory Federal Income Tax (benefit) Rate to Company's Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Unrecognized Tax Benefits Summary [Line Items]
Tax (benefit) at statutory federal rate	34.00%	34.00%
State Tax (benefit)-net of federal benefit	(3.24%)	1.31%
Permanent differences	1.83%	(0.04%)
Credits	1.97%	1.83%
Change in Valuation Allowance	(34.25%)	(37.07%)
Other	(0.31%)	(0.19%)
Provision for Taxes	0.00%	(0.16%)

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax [Line Items]
Net operating loss and tax credit carry forwards use limit	Under Internal Revenue Code Section 382 and related provisions, the benefits from net operating loss and tax credit carry forwards may be limited in the event the Company has a cumulative ownership change of more than 50% over a three year period.
Unrecognized tax benefit	$ 2,569,544	$ 2,516,860	$ 2,409,043
Windfall Stock Based Compensation Deductions
Income Tax [Line Items]
Net operating loss carryforwards	21,000	21,000
Federal Income Tax
Income Tax [Line Items]
Net operating loss carryforwards	$ 112,000,000	107,000,000
Net operating loss carry forwards expire period	Dec. 31, 2025
Tax credit carry forwards available to offset future federal tax liabilities	$ 5,400,000	5,300,000
State Income Tax
Income Tax [Line Items]
Net operating loss carryforwards	$ 104,000,000	102,000,000
Net operating loss carry forwards expire period	Dec. 31, 2017
Tax credit carry forwards available to offset future federal tax liabilities	$ 4,900,000	$ 4,800,000

Unrecognized tax benefit (Detail) - USD ($)	12 Months Ended
Unrecognized tax benefit (Detail) - USD ($)	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits [Line Items]
Beginning Balance at January 1, 2013	$ 2,516,860	$ 2,409,043
Increase/(Decrease) of unrecognized tax benefits related to current year	52,684	107,817
Ending Balance at December 31, 2013	$ 2,569,544	$ 2,516,860

Collaborations - Additional Information (Detail)					3 Months Ended		6 Months Ended		12 Months Ended
Collaborations - Additional Information (Detail)	Apr. 02, 2015	Sep. 16, 2013 USD ($)	Aug. 20, 2013 USD ($) Licenses	Jun. 29, 2009 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Contract revenue					$ 859,000	$ 297,000	$ 1,531,000	$ 594,000	$ 1,812,500	$ 523,308
ISU Abxis
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Deferred revenue recognition period					4 years				4 years
Deferred revenue					$ 948,000		948,000		$ 1,166,667	1,604,167
Contract revenue					109,000	109,000	219,000	219,000	437,500	145,833
ISU Abxis \| Up Front Payment
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amount received for research and development process		$ 1,750,000
Pfizer Inc
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Collaboration contract revenue					750,000	$ 187,500	1,312,500	$ 375,000	1,375,000	312,500	$ 4,200,000	$ 4,200,000
Deferred revenue recognition period				5 years
Deferred revenue					$ 0		$ 0		$ 1,312,500	$ 1,187,500	12,576,667
Milestone and other contingent payments received											7,000,000	4,000,000
Number of Non-refundable annual license maintenance payments \| Licenses			2
Non-refundable annual license maintenance payments			$ 1,500,000
Effective termination notice period	60 days
Pfizer Inc \| Period 1
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
license maintenance payable period			Aug. 01, 2014
Pfizer Inc \| Period 2
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
license maintenance payable period			Aug. 01, 2013
Pfizer Inc \| Up Front Payment
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Amount received for research and development process				$ 21,000,000
Pfizer Inc \| Research Services
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Collaboration contract revenue											$ 1,602,079	$ 2,931,541

Other Income - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Other Income
Operating Leased Assets [Line Items]
Sub-lease rent and operating expense reimbursement	$ 541,720	$ 153,266

Subsequent Event - Additional Information (Detail)							1 Months Ended	6 Months Ended		12 Months Ended
Subsequent Event - Additional Information (Detail)	Aug. 20, 2015	Aug. 15, 2015 USD ($) $ / shares	Jul. 29, 2015 USD ($) shares	May 13, 2015 USD ($) $ / shares	Mar. 01, 2015 USD ($)	Jan. 22, 2015 USD ($) $ / shares shares	Jan. 31, 2015 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Aug. 19, 2015 $ / shares	Dec. 31, 2012 USD ($)
Subsequent Event [Line Items]
Common stock, shares authorized \| shares								160,000,000		110,000,000	104,000,000
Common stock, par value \| $ / shares								$ 0.001		$ 0.001	$ 0.001
Sub lease agreement description										As of February 23, 2015 Catalyst signed a sublease in the same building that they have occupied since the current lease expired on February 28, 2015. The initial term of the sub-lease starts on March 1, 2015 and ends on August 31, 2015. The Sublease also has an extension option that would go through February 27, 2018. On March 1, 2015 the Company issued a letter of Credit in the amount of $56,947 held in the Company’s Money Market account to satisfy the security deposit requested by the sub lessor. The Company also issued a payment to sub lessor in the amount of $368,290 to prepay rent from March through August 31, 2015.
Cash and cash equivalents								$ 2,306,000	$ 4,229,000	$ 1,543,705	$ 2,828,431		$ 3,401,449
Convertible preferred stock, gross cash proceeds								$ 3,260,000	$ 4,983,000	$ 4,981,985	$ 5,742,060
Merger Agreement \| Non Interest Bearing Convertible Notes
Subsequent Event [Line Items]
Note conversion price \| $ / shares								$ 9.19
Series F Convertible Preferred Stock
Subsequent Event [Line Items]
Convertible preferred stock, principal offer amount							$ 3,300,000
Convertible preferred stock, shares issued per share value \| $ / shares							$ 1.2706
Common stock, shares authorized \| shares							160,000,000
Preferred stock, par value \| $ / shares								0.001		$ 0.001
Preferred stock, liquidation preference per share \| $ / shares								$ 6.353		$ 6.353
Convertible preferred stock, shares issued \| shares							2,623,650
Subsequent Event
Subsequent Event [Line Items]
Common stock, shares authorized \| shares						160,000,000
Common stock, par value \| $ / shares						$ 0.001
Preferred stock, par value \| $ / shares						$ 0.001
Security deposit to sub lessor					$ 56,947
Payment to sub lessor					$ 368,290
Subsequent Event \| Merger Agreement
Subsequent Event [Line Items]
Joint announced date				May 13, 2015
Merger agreement date				Mar. 05, 2015
Cash and cash equivalents				$ 40,000,000
Dividends expected to distribute in cash		$ 19,500,000		19,000,000
Escrow available				$ 37,000,000
Subsequent Event \| Merger Agreement \| Catalysts
Subsequent Event [Line Items]
Expected ownership percentage				58.00%
Subsequent Event \| Merger Agreement \| Targacept
Subsequent Event [Line Items]
Expected ownership percentage				42.00%
Subsequent Event \| Merger Agreement \| Convertible Notes Payable
Subsequent Event [Line Items]
Aggregate principal amount				$ 37,000,000
Subsequent Event \| Merger Agreement \| Non Interest Bearing Convertible Notes
Subsequent Event [Line Items]
Joint announced date	May 13, 2015
Merger agreement date	Mar. 05, 2015
Aggregate principal amount		$ 37,000,000
Dividends expected to distribute in non-interest bearing convertible notes				$ 37,000,000
Note conversion price \| $ / shares		$ 1.08		$ 9.19								$ 7.56
Negotiated per-share value				130.00%
Stock split ratio	7			7
Subsequent Event \| Convertible Notes
Subsequent Event [Line Items]
Aggregate principal amount			$ 1,900,000
Convertible notes, accrued interest			$ 30,000
Subsequent Event \| Series F Convertible Preferred Stock
Subsequent Event [Line Items]
Convertible preferred stock, principal offer amount						$ 3,300,000
Convertible preferred stock, shares issued per share value \| $ / shares						$ 1.2706
Convertible preferred stock, conversion shares into common stock shares						The Series F convertible preferred stock has a conversion rate of 101 such that each individual share of Series F convertible preferred stock is convertible into ten shares of common stock.
Preferred stock, liquidation preference per share \| $ / shares						$ 6.3530
Convertible preferred stock, shares issued \| shares			3,164,872
Convertible preferred stock, gross cash proceeds			$ 4,000,000
Convertible notes, shares issued upon conversion \| shares			1,511,723
Warrants issued \| shares			372,045

Nature of Operations and Basis of Presentation - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Aug. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization and Nature of Operations [Line Items]
Corporation incorporated	Aug. 08, 2002
Accumulated deficit	$ (120,857,000)		$ (116,274,661)	$ (109,661,406)
Merger Agreement \| Subsequent Event
Organization and Nature of Operations [Line Items]
Capital including cash and cash equivalents and marketable security		$ 41,100,000

- Definition

Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

+ References + Details

Convertible Notes (Detail) $ in Thousands	Jun. 30, 2015 USD ($)
Debt Instrument [Line Items]
Total convertible notes payable - related party	$ 1,458
Related Party \| Convertible Notes Payable
Debt Instrument [Line Items]
Convertible promissory notes	1,893
Accrued interest	11
Less: Debt discount	(446)
Total convertible notes payable - related party	$ 1,458

Convertible Notes Related Parties - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2015	May 31, 2015
Debt Instrument [Line Items]
Interest expense related to accrued interest and amortization of debt discount		$ 39,000	$ 39,000
Related Party \| Warrant
Debt Instrument [Line Items]
Aggregate fair value of warrants	$ 474,000	474,000	$ 474,000
Fair value assumptions, expected term			5 years
Fair value assumptions, expected volatility			80.00%
Fair value assumptions, dividend yield			0.00%
Related Party \| Warrant \| Minimum
Debt Instrument [Line Items]
Fair value assumptions, risk-free interest rate			0.11%
Related Party \| Warrant \| Maximum
Debt Instrument [Line Items]
Fair value assumptions, risk-free interest rate			0.18%
Related Party \| Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of convertible promissory notes issued and sold	$ 1,900,000	$ 1,900,000	$ 1,900,000	$ 1,900,000
Convertible debt interest rate	12.00%	12.00%	12.00%
Debt instrument maturity period	1 year
Warrants exercisable percentage	25.00%	25.00%	25.00%
Warrants purchase percentage			0.10%
Related Party \| Convertible Notes Payable \| Minimum
Debt Instrument [Line Items]
Aggregate cash proceeds from issuance of debt	$ 3,000,000
Related Party \| Convertible Notes Payable \| Series E Preferred Stock
Debt Instrument [Line Items]
Preferred stock conversion rate per share	$ 1.2706	$ 1.2706	$ 1.2706

Stock Based Compensation - Additional Information (Detail) - 2004 Stock Plan - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised			$ 16,000	$ 0	$ 627,491
Weighted average grant date fair value of options granted	$ 0.14	$ 0.17	$ 0.16	$ 0.16	$ 0.23	$ 0.29
Weighted average grant date fair value of options vested	$ 0.24	$ 0.26	$ 0.25	$ 0.24
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized employee stock based compensation expense	$ 177,000		$ 177,000		$ 173,704	$ 296,963
Unrecognized employee stock based compensation expense, period for recognition			1 year 10 months 6 days		1 year 9 months 29 days

Summary of Stock-Based Compensation Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 39	$ 61	$ 83	$ 133
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	13	19	24	40
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 26	$ 42	$ 59	$ 93

Basic and Diluted Net Loss Per Share (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
Basic and Diluted Net Loss Per Share (Detail) - USD ($)	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss, basic and diluted	$ (1,724,000)	$ (2,075,000)	$ (4,582,000)	$ (3,810,000)	$ (6,613,255)	$ (9,966,337)
Weighted-average number of shares used in computing net loss per share, basic and diluted	9,810,572	9,572,110	9,780,959	9,566,373
Net loss per share, basic and diluted	$ (0.18)	$ (0.22)	$ (0.47)	$ (0.40)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Anti-dilutive Securities (Detail) - shares	6 Months Ended	12 Months Ended
Anti-dilutive Securities (Detail) - shares	Jun. 30, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	99,908,764	94,973,722
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	90,028,661	87,405,011
Options To Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	6,993,784	6,551,183
Convertible Preferred Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	1,335,834	983,778
Convertible Common Stock Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	33,750	33,750
Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible common stock warrants	1,496,735

Merger Agreement - Additional Information (Detail) $ / shares in Units, $ in Millions	Aug. 20, 2015 shares	Aug. 19, 2015 $ / shares	Aug. 15, 2015 USD ($) $ / shares	May 13, 2015 USD ($) $ / shares	Jun. 30, 2015 $ / shares
Merger Agreement \| Non Interest Bearing Convertible Notes
Business Acquisition [Line Items]
Dividend per share					$ 9.19
Subsequent Event \| Merger Agreement
Business Acquisition [Line Items]
Joint announced date				May 13, 2015
Merger agreement date				Mar. 05, 2015
Exchange rate, shares of common stock	0.0382
Dividends expected to distribute in cash \| $			$ 19.5	$ 19.0
Dividend per share		$ 3.9840	$ 0.5692
Subsequent Event \| Merger Agreement \| Targacept
Business Acquisition [Line Items]
Percentage of expected ownership interest				42.00%
Subsequent Event \| Merger Agreement \| Catalysts
Business Acquisition [Line Items]
Percentage of expected ownership interest				58.00%
Subsequent Event \| Merger Agreement \| Non Interest Bearing Convertible Notes
Business Acquisition [Line Items]
Stock split ratio	7			7
Joint announced date	May 13, 2015
Merger agreement date	Mar. 05, 2015
Aggregate principal amount \| $			$ 37.0
Dividend per share		$ 7.56	$ 1.08	$ 9.19
Subsequent Event \| Definitive Agreement and Plan of Merger with Catalyst Biosciences, Inc.
Business Acquisition [Line Items]
Shares of Targacept's common stock outstanding \| shares	11,416,984
Subsequent Event \| Definitive Agreement and Plan of Merger with Catalyst Biosciences, Inc. \| Targacept
Business Acquisition [Line Items]
Percentage of expected ownership interest	59.00%
Subsequent Event \| Definitive Agreement and Plan of Merger with Catalyst Biosciences, Inc. \| Catalysts
Business Acquisition [Line Items]
Percentage of expected ownership interest	53.00%