Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2014	May 19, 2014
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q1
Entity Registrant Name	CERULEAN PHARMA INC.
Entity Central Index Key	0001401914
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		20,123,013

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 8,468,000	$ 5,488,000
Accounts receivable, prepaid expenses, and other current assets	3,033,000	959,000
Total current assets	11,501,000	6,447,000
Property and equipment - Net	223,000	245,000
Other assets	130,000	135,000
Total	11,854,000	6,827,000
Current liabilities:
Current portion of loan payable	3,203,000	3,134,000
Convertible promissory notes payable to shareholders	17,324,000	8,824,000
Accounts payable	2,160,000	914,000
Accrued expenses	1,493,000	2,274,000
Total current liabilities	24,180,000	15,146,000
Long-term liabilities:
Loan payable - net of current portion	2,297,000	3,124,000
Preferred stock warrant liability	424,000	928,000
Noncurrent accrued interest	452,000	391,000
Other	14,000	12,000
Total long-term liabilities	3,187,000	4,455,000
Redeemable convertible preferred stock	81,525,000	81,525,000
Commitments
Stockholders' deficit:
Common stock, $0.0001 par value; 132,000,000 shares and designated, 793,561 and 785,531 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively
Additional paid-in capital	4,315,000	4,140,000
Deficit accumulated during the development stage	(101,353,000)	(98,439,000)
Total stockholders' deficit	(97,038,000)	(94,299,000)
Total	$ 11,854,000	$ 6,827,000

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares designated	132,000,000	132,000,000
Common stock, shares issued	793,561	785,531
Common stock, shares outstanding	793,561	785,531

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		100 Months Ended
Condensed Consolidated Statements of Operations (USD $)	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Income Statement [Abstract]
Revenue	$ 47,000		$ 1,716,000
Operating expenses:
Research and development	1,495,000	3,479,000	68,537,000
General and administrative	1,510,000	1,972,000	33,080,000
Total operating expenses	3,005,000	5,451,000	101,617,000
Other income (expense):
Interest income	1,000	1,000	685,000
Interest expense	(461,000)	(353,000)	(2,856,000)
Decrease in value of preferred stock warrant liability	504,000	231,000	719,000
Total other income (expense) - net	44,000	(121,000)	(1,452,000)
Net loss	(2,914,000)	(5,572,000)	(101,353,000)
Accretion of redeemable convertible preferred stock			(694,000)
Net loss attributable to common stockholders	$ (2,914,000)	$ (5,572,000)	$ (102,047,000)
Net loss per share attributable to common stockholders:
Basic and diluted	$ (3.70)	$ (9.09)	$ (167.93)
Weighted-average common shares outstanding:
Basic and diluted	786,986	612,836	607,682

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended		100 Months Ended
Condensed Consolidated Statements of Cash Flows (USD $)	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Cash flows from operating activities:
Net loss	$ (2,914,000)	$ (5,572,000)	$ (101,353,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	148,000	153,000	2,461,000
Noncash research and development expense			202,000
Noncash rent expense	2,000	(12,000)	15,000
Change in carrying value of preferred stock warrant liability	(504,000)	(231,000)	(719,000)
Depreciation and amortization	36,000	71,000	1,965,000
Loss on disposal of property and equipment			56,000
Noncash interest expense	120,000	163,000	988,000
Changes in operating assets and liabilities:
Accounts receivable, prepaid expenses and other current assets	(1,019,000)	161,000	(1,586,000)
Accounts payable	1,246,000	1,060,000	2,160,000
Accrued expenses	(781,000)	(395,000)	1,493,000
Net cash used in operating activities	(3,666,000)	(4,602,000)	(94,318,000)
Cash flows from investing activities:
Purchases of property and equipment	(14,000)	(2,000)	(2,234,000)
Proceeds from sale of property and equipment	10,000		14,000
Increase in restricted cash			(117,000)
Net cash used in investing activities	(4,000)	(2,000)	(2,337,000)
Cash flows from financing activities:
Payments on capital lease			(15,000)
Proceeds from sale of common stock	27,000	16,000	120,000
Proceeds from issuance of convertible promissory notes	8,500,000		24,324,000
Proceeds from loans payable			10,695,000
Payments on loans payable	(812,000)	(748,000)	(4,837,000)
Cash paid for deferred financing costs	(1,065,000)		(1,497,000)
Proceeds from sale of redeemable convertible preferred stock - net of issuance costs			76,333,000
Net cash provided by (used in) financing activities	6,650,000	(732,000)	105,123,000
Net increase (decrease) in cash and cash equivalents	2,980,000	(5,336,000)	8,468,000
Cash and cash equivalents - Beginning of period	5,488,000	16,707,000
Cash and cash equivalents - End of period	8,468,000	11,371,000	8,468,000
Supplemental disclosures of noncash investing and financing activities:
Conversion of redeemable convertible preferred stock into common stock			2,226,000
Property and equipment acquired under capital lease			15,000
Accretion of redeemable convertible preferred stock to redemption value			694,000
Fair value of preferred stock warrants issued in connection with debt		182,000	1,143,000
Supplemental cash flow information - Interest paid	126,000	190,000	1,419,000
Redeemable Convertible Preferred Stock [Member]
Supplemental disclosures of noncash investing and financing activities:
Conversion of accrued interest and convertible notes payable			522,000
Series C Redeemable Convertible Preferred Stock [Member]
Supplemental disclosures of noncash investing and financing activities:
Conversion of accrued interest and convertible notes payable			$ 6,676,000

Nature of Business and Operations

3 Months Ended

Mar. 31, 2014

Accounting Policies [Abstract]

Nature of Business and Operations

1.	NATURE OF BUSINESS AND OPERATIONS

Nature of Business — Cerulean Pharma Inc. (the “Company”) was incorporated on November 28, 2005 as a Delaware corporation and is located in Cambridge, Massachusetts. The Company was formed to develop novel, nanotechnology-based therapeutics in the areas of oncology and other diseases. During 2013, the Company formed a wholly-owned subsidiary, Cerulean Pharma Australia Pty Ltd as an Australian-based proprietary limited company. The activity in the subsidiary to date has been insignificant.

Basis of Presentation – The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All intercompany accounts and transactions have been eliminated. The consolidated interim financial statements of the Company included herein have been prepared, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these consolidated financial statements should be read in conjunction with the financial statements as of and for the year ended December 31, 2013 and notes thereto, included in the Company’s prospectus filed with the SEC pursuant to Rule 424(b)(4) on April 14, 2014 (the “Prospectus”).

The unaudited interim consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited interim consolidated financial statements contain all adjustments which are necessary to present fairly the Company’s financial position as of March 31, 2014 and the results of its operations and cash flows for the three months ended March 31, 2014 and 2013 and the period from November 28, 2005 (date of incorporation) to March 31, 2014. Such adjustments are of a normal and recurring nature. The results for the three months ended March 31, 2014 are not indicative of the results for the year ending December 31, 2014, or for any future period.

On April 15, 2014, the Company completed the sale of 8,500,000 shares of its common stock in its initial public offering (the “IPO”), at a price to the public of $7.00 per share, resulting in net proceeds to the Company of $53.2 million after deducting underwriting discounts and commissions and offering expenses payable by the Company. On May 7, 2014, the Company completed the sale of an additional 1,069,715 shares of common stock at a price to the public of $7.00 per share under a partial exercise by the underwriters of their option to purchase additional shares of common stock, resulting in net proceeds to the Company of $7.0 million after deducting underwriting discounts and commissions.

In preparation for the IPO, the Company’s board of directors and stockholders approved a 1-for-14.5074 reverse stock split of the Company’s common stock effective March 31, 2014. All share and per share amounts in the consolidated financial statements contained herein and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding redeemable convertible preferred stock and convertible notes automatically converted into shares of common stock as of April 15, 2014, resulting in the issuance by the Company of an additional 9,728,237 shares of common stock. The significant increase in shares outstanding in April 2014 is expected to impact the year-over-year comparability of the Company’s net loss per share calculations over the next year.

In connection with the completion of the IPO on April 15, 2014 the Company’s outstanding warrants to purchase 1,857,226 shares of the Company’s preferred stock automatically converted into warrants to purchase an aggregate of 128,663 shares of the Company’s common stock and as a result the Company reclassified the warrant liability to additional paid-in capital.

Significant Accounting Policies

3 Months Ended

Mar. 31, 2014

Accounting Policies [Abstract]

Significant Accounting Policies

2.	SIGNIFICANT ACCOUNTING POLICIES

There have been no material changes to the significant accounting policies previously disclosed in the Company’s Prospectus.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

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Net Loss Per Share Attributable to Common Stockholders

3 Months Ended

Mar. 31, 2014

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

3.	NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding for the period. During periods in which the Company earns net income, the Company would allocate participating securities a proportional share of net income determined by dividing total weighted average participating securities by the sum of the total weighted average common shares and participating securities (the “two-class method”). The Company’s preferred stock participates in dividends declared by the Company and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods in which the Company earns net income. During periods in which the Company incurs a net loss, the Company allocates no portion of the loss to participating securities because they have no contractual obligation to share in the losses of the Company. The Company computes diluted loss per common share after giving consideration to the dilutive effect of stock options, warrants and unvested restricted stock that are outstanding to the period, except where the inclusion of such nonparticipating securities would be antidilutive.

The Company has reported a net loss for all periods presented and, therefore diluted net loss per common share is the same as basic net loss per common share.


	Three Months Ended March 31,
	2014			2013
Net loss	$	(2,914,000	)	$	(5,572,000	)
Accretion of preferred stock issuance costs to redemption value		—			—

Net loss attributable to common stockholders — basic and diluted	$	(2,914,000	)	$	(5,572,000	)

Weighted-average number of common shares — basic and diluted		786,986			612,836
Net loss per share attributable to common stockholders — basic and diluted	$	(3.70	)	$	(9.09	)

The following potentially dilutive securities that were outstanding, prior to the use of the two-class method, have been excluded from the computation of diluted weighted-average shares outstanding, because the inclusion of such securities would have an antidilutive impact due to the losses reported (in common stock equivalent shares):


	As of March 31, 2014		As of March 31, 2013
Options to purchase common stock		1,208,077		1,142,838
Warrants to purchase redeemable convertible preferred stock		128,663		128,663
Redeemable convertible preferred stock		6,826,004		6,992,694
Convertible notes payable		2,894,099		—

- Definition

The entire disclosure for earnings per share.

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Accrued Expenses

3 Months Ended

Mar. 31, 2014

Payables And Accruals [Abstract]

Accrued Expenses

4.	ACCRUED EXPENSES

Accrued expenses consist of the following:


	As of March 31, 2014		As of December 31, 2013
Accrued expenses	$	236,000	$	379,000
Accrued clinical trial costs		245,000		610,000
Accrued contract manufacturing expenses		344,000		433,000
Accrued interest		449,000		234,000
Accrued compensation and benefits		219,000		618,000

Total accrued expenses	$	1,493,000	$	2,274,000

Convertible Notes Payable to Shareholders

3 Months Ended

Mar. 31, 2014

Debt Disclosure [Abstract]

Convertible Notes Payable to Shareholders

5.	CONVERTIBLE NOTES PAYABLE TO SHAREHOLDERS

In 2014, the Company issued convertible promissory notes in the aggregate amount of $6,000,000 to existing investors and a convertible promissory note in the amount of $2,500,000 to a new investor. All the notes have a stated interest rate of 7%, and are payable within 30 days of written demand by the holders of at least 60% of the aggregate principal amount outstanding under the notes after February 26, 2015. Outstanding principal and unpaid accrued interest due under the notes were automatically converted into shares of the Company’s common stock upon the closing of the Company’s IPO on April 15, 2014, at a conversion price equal to 77.5% of the IPO price. The Company will record a non-cash charge in the second quarter of 2014, equal to the difference between the fair value of the shares into which the notes converted and the carrying amount of the notes.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

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Stock Option Plan

3 Months Ended

Mar. 31, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Option Plan

6.	STOCK OPTION PLAN

2007 Stock Incentive Plan

The Company has recorded aggregate stock-based compensation expense related to the issuance of stock option awards in the following line items in the accompanying consolidated statement of operations:


	Three Months Ended March 31,
	2014		2013
Research and development	$	53,000	$	56,000
General and administrative		95,000		97,000

Total	$	148,000	$	153,000

The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model based on the assumptions noted in the table below. Expected volatility for the Company’s common stock was determined based on an average of the historical volatility of a peer-group of similar public companies. The Company has limited option exercise information, as such; the expected term of the options granted was calculated using the simplified method that represents the average of the contractual term of the option and the weighted-average vesting period of the option. The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future. The risk-free rate for periods within the contractual life of the option is based upon the U.S. Treasury yield curve in effect at the time of grant.

The assumptions used in the Black-Scholes option-pricing model for stock options granted to employees and directors in exchange for board services during the three months ended March 31, 2014 and 2013 are as follows:


	March 31,
	2014			2013

Expected life		6 years			6 years
Risk-free interest rate		1.83%-2.00	%		1.09	%
Expected volatility		60	%		79	%
Expected dividend rate		—	%		—	%

A summary of stock option activity for employee, directors and nonemployee awards under the 2007 Stock Incentive Plan (the “2007 Plan”) during the three months ended March 31, 2014 is presented below:


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding — January 1, 2014		1,062,694		$	3.98		7.2	$	7,028,000
Granted		159,610		$	10.59
Exercised		(8,030	)	$	3.34
Forfeited		(6,197	)	$	5.76

Outstanding — March 31, 2014		1,208,077		$	4.85		7.4	$	3,169,000

Options expected to vest — March 31, 2014		543,449		$	5.62		8.7	$	1,267,000

Options exercisable — March 31, 2014		637,169		$	4.16		6.1	$	1,839,000

The weighted-average per share grant date fair value of options granted during the three months ended March 31, 2014 and 2013 was $5.95 and $2.67, respectively.

The Company has recorded stock-based compensation expense related to nonemployee awards of $12,000, and $9,000 for the three months ended March 31, 2014 and 2013, respectively. The compensation expense related to the nonemployee awards is included in the total stock-based compensation each year and is subject to re-measurement until the options vest. The Black-Scholes assumptions used to estimate fair value for the three months ended March 31, 2014 and 2013, respectively, were as follows: risk-free rate of 2.11% to 2.63% and 1.11% to 1.49%, estimated volatility of 56% to 59% and 76% to 79%, remaining contractual life of 8 and 7 years and no expected dividends, respectively. The Company did not grant any nonemployee stock option grants for the three months ended March 31, 2014 and 2013, except for a performance award grant in 2013, to the board chairman for non-board related services.

2014 Stock Incentive Plan

In March 2014, the Company’s board of directors adopted and its stockholders approved the 2014 Stock Incentive Plan (the “2014 Plan”), which became effective upon the closing of the IPO. The 2014 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards. Upon effectiveness of the 2014 Plan, the number of shares of the Company’s common stock that were reserved for issuance under the 2014 Plan was equal to the sum of (1) 2,400,000 shares plus (2) the number of shares (up to 1,221,651 shares) equal to the sum of the number of shares of the Company’s common stock then available for grant under the 2007 Plan and the number of shares of the Company’s common stock subject to outstanding awards under the 2007 Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right (subject, in the case of incentive stock options, to any limitation of the Internal Revenue Code) plus (3) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2015 and continuing until, and including, the fiscal year ending December 31, 2024, equal to the least of (A) 1,000,000 shares of the Company’s common stock (B) 4% of the number of shares of the Company’s common stock outstanding on the first day of the fiscal year, or (C) an amount determined by the Company’s board of directors.

2014 Employee Stock Purchase Plan

In March 2014, the Company’s board of directors adopted and its stockholders approved the 2014 employee stock purchase plan (the “2014 ESPP”), which became effective upon the closing of the IPO. The 2014 ESPP will be administered by the Company’s board of directors or by a committee appointed by the Company’s board of directors. The 2014 ESPP initially provides participating employees with the opportunity to purchase up to an aggregate 500,000 of shares of the Company’s common stock. The number of shares of the Company’s common stock reserved for issuance under the 2014 ESPP will automatically increase on the first day of each fiscal year, commencing on January 1, 2015 and ending January 1, 2024, in an amount equal to the least of (i) 600,000 shares of the Company’s common stock, (ii) 1% of the total number of shares of the Company’s common stock outstanding on the first day of the applicable year, or (iii) an amount determined by the Company’s board of directors.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

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Fair Value Measurements

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Measurements

7.	FAIR VALUE MEASUREMENTS

The Company’s financial instruments consist of cash equivalents, accounts payable, accrued expenses, debt obligations, and preferred stock warrants. The carrying amount of accounts payable and accrued expenses are considered a reasonable estimate of their fair value, due to the short-term maturity of these instruments. The carrying amount of debt is also considered to be a reasonable estimate of the fair value based on the short term nature of the debt and because the debt bears interest at the prevailing market rate for instruments with similar characteristics.

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value are performed in a manner to maximize the use of observable inputs and minimize the use of unobservable inputs.

The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, which are the following:

Level 1 — Quoted prices in active markets that are accessible at the market date for identical unrestricted assets or liabilities.

Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs for which all significant inputs 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 activity and that are significant to the fair value of the assets or liabilities.

A summary of the financial assets and liabilities that are measured on a recurring basis at fair value as of March 31, 2014 and December 31, 2013, is as follows:


			Fair Value Measurements Using
	Carrying Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
March 31, 2014
Money market funds	$	7,883,000	$	—	$	7,883,000	$	—
Preferred stock warrant liability		424,000		—		—		424,000
December 31, 2013
Money market funds	$	5,233,000	$	—	$	5,233,000	$	—
Preferred stock warrant liability		928,000		—		—		928,000

The convertible notes payable and loan agreements are Level 2 measurements in the fair value hierarchy.

The Company’s money market funds have been valued on the basis of valuations provided by third-party pricing services, as derived from such services’ pricing models. Inputs to the models may include, but are not limited to, reported trades, executable bid and asked prices, broker/dealer quotations, prices or yields of securities with similar characteristics, benchmark curves or information pertaining to the issuer, as well as industry and economic events. The pricing services may use a matrix approach, which considers information regarding securities with similar characteristics to determine the valuation for a security. The Company is ultimately responsible for the consolidated financial statements and underlying estimates. Accordingly, the Company assesses the reasonableness of the valuations provided by the third-party pricing services by reviewing actual trade data, broker/dealer quotes and other similar data, which are obtained from quoted market prices or other sources.

No transfers between levels have occurred during the periods presented.

The reconciliation of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows:


	Preferred Stock Warrant
	Series B			Series C			Series D			Total
Balance — December 31, 2012	$	7,000		$	500,000		$	623,000		$	1,130,000

Decrease in fair value recorded in other income		(3,000	)		(116,000	)		(112,000	)		(231,000	)

Balance — March 31, 2013	$	4,000		$	384,000		$	511,000		$	899,000


	Preferred Stock Warrant
	Series B			Series C			Series D			Total
Balance — December 31, 2013	$	4,000		$	386,000		$	538,000		$	928,000

Decrease in fair value recorded in other income		(2,000	)		(229,000	)		(273,000	)		(504,000	)

Balance — March 31, 2014	$	2,000		$	157,000		$	265,000		$	424,000

The Company’s warrants were valued using the Black-Scholes option-pricing model. The following assumptions were used in the Black-Scholes option pricing model to determine the fair value of the preferred stock warrant liability:


	March 31,	December 31,
	2014	2013

Expected life	4-8 years	4-8 years
Risk-free interest rate	2.23%-2.72%	2.29%-2.90%
Expected volatility	64%-65%	64%-65%
Expected dividend rate	— %	— %

The preferred stock warrant liability was reclassified into additional paid-in capital at the fair value in connection with the IPO on April 15, 2014.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

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Income Taxes

3 Months Ended

Mar. 31, 2014

Income Tax Disclosure [Abstract]

Income Taxes

8.	INCOME TAXES

The Company did not record a federal or state income tax benefit for the Company’s losses for the three months ended March 31, 2014 and 2013 due to the Company’s conclusion that the valuation allowance is required.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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Related Party Transactions

3 Months Ended

Mar. 31, 2014

Related Party Transactions

9.	RELATED PARTY TRANSACTIONS

In February 2014, the Company issued convertible promissory notes to existing investors, as described in Note 5.

In April 2013, the Company entered into a laboratory, equipment sharing, services and license agreement with an entity affiliated with one of the Company’s directors. Fees recorded offsetting research and development expenses under this agreement and paid in the three months ended March 31, 2014 were $44,500. This agreement was terminated on April 1, 2014. On April 1, 2014, the Company sold used equipment to this entity and received proceeds for sale of equipment of $30,000 from such sale.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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Net Loss Per Share Attributable to Common Stockholders (Tables)

3 Months Ended

Mar. 31, 2014

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss Per Common Share

The Company has reported a net loss for all periods presented and, therefore diluted net loss per common share is the same as basic net loss per common share.


	Three Months Ended March 31,
	2014			2013
Net loss	$	(2,914,000	)	$	(5,572,000	)
Accretion of preferred stock issuance costs to redemption value		—			—

Net loss attributable to common stockholders — basic and diluted	$	(2,914,000	)	$	(5,572,000	)

Weighted-average number of common shares — basic and diluted		786,986			612,836
Net loss per share attributable to common stockholders — basic and diluted	$	(3.70	)	$	(9.09	)

Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding


	As of March 31, 2014		As of March 31, 2013
Options to purchase common stock		1,208,077		1,142,838
Warrants to purchase redeemable convertible preferred stock		128,663		128,663
Redeemable convertible preferred stock		6,826,004		6,992,694
Convertible notes payable		2,894,099		—

Accrued Expenses (Tables)

3 Months Ended

Mar. 31, 2014

Payables And Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses consist of the following:


	As of March 31, 2014		As of December 31, 2013
Accrued expenses	$	236,000	$	379,000
Accrued clinical trial costs		245,000		610,000
Accrued contract manufacturing expenses		344,000		433,000
Accrued interest		449,000		234,000
Accrued compensation and benefits		219,000		618,000

Total accrued expenses	$	1,493,000	$	2,274,000

Stock Option Plan (Tables)

3 Months Ended

Mar. 31, 2014

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Stock-based Compensation Expense


	Three Months Ended March 31,
	2014		2013
Research and development	$	53,000	$	56,000
General and administrative		95,000		97,000

Total	$	148,000	$	153,000

Summary of Assumptions Used in Black-Scholes Option-Pricing Model for Stock Options Granted to Employees and Directors in Exchange for Board Services


	March 31,
	2014			2013

Expected life		6 years			6 years
Risk-free interest rate		1.83%-2.00	%		1.09	%
Expected volatility		60	%		79	%
Expected dividend rate		—	%		—	%

Summary of Stock Option Activity for Employee, Directors and Nonemployee Awards under 2007 Stock Incentive Plan ("2007 Plan")


	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding — January 1, 2014		1,062,694		$	3.98		7.2	$	7,028,000
Granted		159,610		$	10.59
Exercised		(8,030	)	$	3.34
Forfeited		(6,197	)	$	5.76

Outstanding — March 31, 2014		1,208,077		$	4.85		7.4	$	3,169,000

Options expected to vest — March 31, 2014		543,449		$	5.62		8.7	$	1,267,000

Options exercisable — March 31, 2014		637,169		$	4.16		6.1	$	1,839,000

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Fair Value Disclosures [Abstract]

Summary of Financial Assets and Liabilities Measured on Recurring Basis at Fair Value

A summary of the financial assets and liabilities that are measured on a recurring basis at fair value as of March 31, 2014 and December 31, 2013, is as follows:


			Fair Value Measurements Using
	Carrying Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
March 31, 2014
Money market funds	$	7,883,000	$	—	$	7,883,000	$	—
Preferred stock warrant liability		424,000		—		—		424,000
December 31, 2013
Money market funds	$	5,233,000	$	—	$	5,233,000	$	—
Preferred stock warrant liability		928,000		—		—		928,000

Reconciliation of Company's Liabilities Measured at Fair Value on Recurring Basis Using Unobservable Inputs (Level3)

The reconciliation of the Company’s liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3) is as follows:


	Preferred Stock Warrant
	Series B			Series C			Series D			Total
Balance — December 31, 2012	$	7,000		$	500,000		$	623,000		$	1,130,000

Decrease in fair value recorded in other income		(3,000	)		(116,000	)		(112,000	)		(231,000	)

Balance — March 31, 2013	$	4,000		$	384,000		$	511,000		$	899,000


	Preferred Stock Warrant
	Series B			Series C			Series D			Total
Balance — December 31, 2013	$	4,000		$	386,000		$	538,000		$	928,000

Decrease in fair value recorded in other income		(2,000	)		(229,000	)		(273,000	)		(504,000	)

Balance — March 31, 2014	$	2,000		$	157,000		$	265,000		$	424,000

Fair Value of Preferred Stock Warrant Liability Calculated by Black-Scholes Option Pricing Model

The following assumptions were used in the Black-Scholes option pricing model to determine the fair value of the preferred stock warrant liability:


	March 31,	December 31,
	2014	2013

Expected life	4-8 years	4-8 years
Risk-free interest rate	2.23%-2.72%	2.29%-2.90%
Expected volatility	64%-65%	64%-65%
Expected dividend rate	— %	— %

- Definition

Tabular disclosure of the fair value measurement of liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of liability.

+ References+ Details

Nature of Business and Operations - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		3 Months Ended	0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 IPO [Member]	May 07, 2014 IPO [Member] Subsequent Event [Member]	Apr. 15, 2014 IPO [Member] Subsequent Event [Member]	Apr. 15, 2014 IPO [Member] Subsequent Event [Member] Preferred Stock [Member]	Apr. 15, 2014 IPO [Member] Subsequent Event [Member] Common Stock [Member]
Enterprise Wide Disclosures [Line Items]
Date of Company's incorporation	Nov. 28, 2005
Common stock issuance date			Apr. 15, 2014
Sale of common stock in IPO					8,500,000
Common stock price per share					$ 7.00
Proceeds from issuance of common stock				$ 7.0	$ 53.2
Common stock issued	793,561	785,531		1,069,715
Common stock issued price per share				$ 7.00
Reverse stock split of common stock			The Company’s board of directors and stockholders approved a 1-for-14.5074 reverse stock split of the Company’s common stock effective March 31, 2014.
Reverse stock split, conversion ratio	14.5074
Convertible preferred stock, shares issued upon conversion					9,728,237
Preferred stock conversion basis			In connection with the closing of the IPO, all of the Company's outstanding redeemable convertible preferred stock and convertible notes automatically converted into shares of common stock as of April 15, 2014
Conversion of warrants						1,857,226	128,663

Net Loss Per Share Attributable to Common Stockholders - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]
Allocation of net loss to participating securities	$ 0
Contractual obligation to share in losses of the Company	$ 0

Net Loss Per Share Attributable To Common Stockholders - Schedule of Basic and Diluted Net Loss Per Common Share (Detail) (USD $)	3 Months Ended		100 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Earnings Per Share [Abstract]
Net loss	$ (2,914,000)	$ (5,572,000)	$ (101,353,000)
Accretion of preferred stock issuance costs to redemption value
Net loss attributable to common stockholders - basic and diluted	$ (2,914,000)	$ (5,572,000)
Weighted-average number of common shares - basic and diluted	786,986	612,836	607,682
Net loss per share attributable to common stockholders - basic and diluted	$ (3.70)	$ (9.09)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 20

-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.19)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.18)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.22)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 5

+ Details

Net Loss Per Share Attributable to Common Stockholders - Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Detail)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average shares outstanding	1,208,077	1,142,838
Warrants to Purchase Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average shares outstanding	128,663	128,663
Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average shares outstanding	6,826,004	6,992,694
Convertible Notes Payable [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted weighted-average shares outstanding	2,894,099

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References+ Details

Accrued Expenses - Schedule of Accrued Expenses (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Payables And Accruals [Abstract]
Accrued expenses	$ 236,000	$ 379,000
Accrued clinical trial costs	245,000	610,000
Accrued contract manufacturing expenses	344,000	433,000
Accrued interest	449,000	234,000
Accrued compensation and benefits	219,000	618,000
Total accrued expenses	$ 1,493,000	$ 2,274,000

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References+ Details

Convertible Notes Payable to Shareholders - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Debt Instrument [Line Items]
Debt instrument percentage	77.50%
Debt instrument interest rate percentage	7.00%
Debt instrument, Period	30 days
Minimum percentage of outstanding notes to trigger payment after maturity date	60.00%
IPO closure date	April 15, 2014
Existing Investors [Member] \| Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Aggregate amount	$ 6,000,000
New Investor [Member] \| Convertible Promissory Notes [Member]
Debt Instrument [Line Items]
Debt instrument, Aggregate amount	$ 2,500,000

Stock Option Plan - Schedule of Stock-based Compensation Expense (Detail) (2007 Stock Incentive Plan [Member], USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 148,000	$ 153,000
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	53,000	56,000
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 95,000	$ 97,000

Stock Option Plan - Summary of Assumptions Used in Black-Scholes Option-Pricing Model for Stock Options Granted to Employees and Directors in Exchange for Board Services (Detail) (2007 Stock Incentive Plan [Member])	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
2007 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	6 years	6 years
Risk-free interest rate, minimum	1.83%
Risk-free interest rate, maximum	2.00%
Risk-free interest rate		1.09%
Expected volatility	60.00%	79.00%
Expected dividend rate

Stock Option Plan - Summary of Stock Option Activity for Employee, Directors and Nonemployee Awards under 2007 Stock Incentive Plan ("2007 Plan") (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding, Beginning balance	1,062,694
Number of Shares, Granted	159,610
Number of Shares, Exercised	(8,030)
Number of Shares, Forfeited	(6,197)
Number of Shares, Outstanding, Ending balance	1,208,077	1,062,694
Number of Shares, Options expected to vest	543,449
Number of Shares, Options exercisable	637,169
Weighted-Average Exercise Price, Outstanding, Beginning balance	$ 3.98
Weighted-Average Exercise Price, Granted	$ 10.59
Weighted-Average Exercise Price, Exercised	$ 3.34
Weighted-Average Exercise Price, Forfeited	$ 5.76
Weighted-Average Exercise Price, Outstanding, Ending balance	$ 4.85	$ 3.98
Weighted-Average Exercise Price, Options expected to vest	$ 5.62
Weighted-Average Exercise Price, Options exercisable	$ 4.16
Weighted-Average Remaining Contractual Life (Years)	7 years 4 months 24 days	7 years 2 months 12 days
Options expected to vest - March 31, 2014	8 years 8 months 12 days
Options exercisable - March 31, 2014	6 years 1 month 6 days
Aggregate Intrinsic Value, Outstanding, Beginning balance	$ 7,028,000
Aggregate Intrinsic Value, Outstanding, Ending balance	3,169,000	7,028,000
Aggregate Intrinsic Value, Options expected to vest	1,267,000
Aggregate Intrinsic Value, Options exercisable	$ 1,839,000

Stock Option Plan - Additional Information (Detail) (USD $)	3 Months Ended					1 Months Ended	3 Months Ended		3 Months Ended	0 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 2007 Stock Incentive Plan [Member]	Mar. 31, 2013 2007 Stock Incentive Plan [Member]	Mar. 31, 2014 2007 Stock Incentive Plan [Member] Non Employee Awards [Member]	Mar. 31, 2013 2007 Stock Incentive Plan [Member] Non Employee Awards [Member]	Mar. 31, 2014 2014 Stock Incentive Plan [Member]	Mar. 31, 2014 2014 Stock Incentive Plan [Member]	Mar. 31, 2014 2014 Stock Incentive Plan [Member] Minimum [Member]	Mar. 31, 2014 2014 Employee Stock Purchase Plan [Member]	Jan. 01, 2015 2014 Employee Stock Purchase Plan [Member] Scenario, Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average per share grant date fair value of options granted		$ 5.95	$ 2.67
Stock-based compensation expense		$ 148,000	$ 153,000	$ 12,000	$ 9,000
Risk-free rate, minimum		1.83%		2.11%	1.11%
Risk-free rate, maximum		2.00%		2.63%	1.49%
Estimated volatility, minimum				56.00%	76.00%
Estimated volatility, maximum				59.00%	79.00%
Remaining contractual life		6 years	6 years	8 years	7 years
Expected dividends				$ 0	$ 0
Options granted to purchase common stock, Number of shares	159,610			0	0
Common stock reserved for issuance						2,400,000	2,400,000	1,000,000	500,000	600,000
Shares available for future grant						1,221,651	1,221,651
Stock option plan, Description							Upon effectiveness of the 2014 Plan, the number of shares of the Company’s common stock that were reserved for issuance under the 2014 Plan was equal to the sum of (1) 2,400,000 shares plus (2) the number of shares (up to 1,221,651 shares) equal to the sum of the number of shares of the Company’s common stock then available for grant under the 2007 Plan and the number of shares of the Company’s common stock subject to outstanding awards under the 2007 Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right (subject, in the case of incentive stock options, to any limitation of the Internal Revenue Code) plus (3) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2015 and continuing until, and including, the fiscal year ending December 31, 2024, equal to the least of (A) 1,000,000 shares of the Company’s common stock (B) 4% of the number of shares of the Company’s common stock outstanding on the first day of the fiscal year, or (C) an amount determined by the Company’s board of directors.		The 2014 ESPP initially provides participating employees with the opportunity to purchase up to an aggregate 500,000 of shares of the Company’s common stock. The number of shares of the Company’s common stock reserved for issuance under the 2014 ESPP will automatically increase on the first day of each fiscal year, commencing on January 1, 2015 and ending January 1, 2024, in an amount equal to the least of (i) 600,000 shares of the Company’s common stock, (ii) 1% of the total number of shares of the Company’s common stock outstanding on the first day of the applicable year, or (iii) an amount determined by the Company’s board of directors.
Percentage of common stock outstanding stock on first day of the year						4.00%				1.00%

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured on Recurring Basis at Fair Value (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 7,883,000	$ 5,233,000
Preferred stock warrant liability	424,000	928,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds
Preferred stock warrant liability
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	7,883,000	5,233,000
Preferred stock warrant liability
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds
Preferred stock warrant liability	$ 424,000	$ 928,000

Fair Value Measurements - Reconciliation of Company's Liabilities Measured at Fair Value on Recurring Basis Using Unobservable Inputs (Level3) (Detail) (Significant Unobservable Inputs (Level 3) [Member], USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities measured at fair value on recurring basis using unobservable inputs, Beginning balance	$ 928,000	$ 1,130,000
Decrease in fair value recorded in other income	(504,000)	(231,000)
Liabilities measured at fair value on recurring basis using unobservable inputs, Ending balance	424,000	899,000
Preferred Stock Warrant, Series B [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities measured at fair value on recurring basis using unobservable inputs, Beginning balance	4,000	7,000
Decrease in fair value recorded in other income	(2,000)	(3,000)
Liabilities measured at fair value on recurring basis using unobservable inputs, Ending balance	2,000	4,000
Preferred Stock Warrant, Series C [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities measured at fair value on recurring basis using unobservable inputs, Beginning balance	386,000	500,000
Decrease in fair value recorded in other income	(229,000)	(116,000)
Liabilities measured at fair value on recurring basis using unobservable inputs, Ending balance	157,000	384,000
Preferred Stock Warrant, Series D [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Liabilities measured at fair value on recurring basis using unobservable inputs, Beginning balance	538,000	623,000
Decrease in fair value recorded in other income	(273,000)	(112,000)
Liabilities measured at fair value on recurring basis using unobservable inputs, Ending balance	$ 265,000	$ 511,000

Fair Value Measurements - Fair Value of Preferred Stock Warrant Liability Calculated by Black-Scholes Option Pricing Model (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected dividend rate
Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected life	4 years	4 years
Risk-free interest rate	2.23%	2.29%
Expected volatility	64.00%	64.00%
Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected life	8 years	8 years
Risk-free interest rate	2.72%	2.90%
Expected volatility	65.00%	65.00%

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]
Federal income tax benefit	$ 0	$ 0
State income tax benefit	$ 0	$ 0

Related Party Transactions - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Commitment Contingency And Related Party Transactions [Abstract]
Fees recorded offsetting research and development expenses	$ 44,500
Agreement termination date	Apr. 01, 2014
Proceeds from sale of equipment	$ 30,000