Achillion Pharmaceuticals 10-Q 7 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	ACHN
Entity Registrant Name	ACHILLION PHARMACEUTICALS INC
Entity Central Index Key	1070336
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		117,558,885

Balance_Sheets

Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$46,723	$73,664
Marketable securities	206,518	79,215
Accounts and other receivables	806	95
Prepaid expenses and other current assets	1,531	1,901
Total current assets	255,578	154,875
Marketable securities	21,914
Fixed assets, net	1,718	1,726
Deferred financing costs and other assets	53	54
Restricted cash	152	152
Total assets	279,415	156,807
Current liabilities:
Accounts payable	8,015	6,418
Accrued expenses	4,786	6,446
Current portion of long-term debt	213	195
Total current liabilities	13,014	13,059
Long-term debt	400	279
Total liabilities	13,414	13,338
Commitments and contingencies (Note 13)
Stockholders' equity:
Common Stock, $0.001 par value; 200,000 shares authorized: 117,558 and 103,594 shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively	118	104
Additional paid-in capital	735,780	599,796
Stock subscription receivable		-5,737
Accumulated deficit	-469,945	-450,682
Accumulated other comprehensive income (loss)	48	-12
Total stockholders' equity	266,001	143,469
Total liabilities and stockholders' equity	$279,415	$156,807

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Per Share data, unless otherwise specified
Common stock, par value	$0.00	$0.00
Common Stock, shares authorized	200,000	200,000
Common Stock, shares issued	117,558	103,594
Common Stock, shares outstanding	117,558	103,594

Statements_of_Comprehensive_Lo

Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenue	$0	$0
Operating expenses
Research and development	15,156	12,842
General and administrative	4,243	3,393
Total operating expenses	19,399	16,235
Loss from operations	-19,399	-16,235
Other income (expense)
Interest income	152	158
Interest expense	-16	-11
Net loss	-19,263	-16,088
Total comprehensive loss (Note 11)	($19,203)	($16,070)
Basic and diluted net loss per share (Note 5)	($0.17)	($0.17)
Weighted average number of shares used in computing basic and diluted net loss per share	111,202	96,792

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net loss	($19,263)	($16,088)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	160	111
Noncash stock-based compensation	2,917	1,556
Premium on purchase of marketable securities	-1,039	-541
Amortization of premium on marketable securities	385	600
Changes in operating assets and liabilities:
Accounts and other receivables	-711	-153
Prepaid expenses and other assets	370	992
Accounts payable	1,522	-950
Accrued expenses	-1,662	1,115
Net cash used in operating activities	-17,321	-13,358
Cash flows from investing activities
Purchases of fixed assets	-74	-218
Purchases of marketable securities	-209,108	-41,518
Maturities of marketable securities	60,605	55,921
Net cash (used in) provided by investing activities	-148,577	14,185
Cash flows from financing activities
Proceeds from the issuance of common stock in connection with public offerings, net of issuance costs	138,291
Proceeds from exercise of stock options	527	5
Payment of deferred financing costs		-77
Borrowings of debt	229
Repayments of debt	-90	-91
Net cash provided by (used in) financing activities	138,957	-163
Net (decrease) increase in cash and cash equivalents	-26,941	664
Cash and cash equivalents, beginning of period	73,664	33,457
Cash and cash equivalents, end of period	46,723	34,121
Supplemental disclosure of cash flow information
Cash paid for interest	21	12
Supplemental disclosure of non-cash financing information
Cashless exercise of warrants	$53

Nature_of_the_Business

Nature of the Business	3 Months Ended
	Mar. 31, 2015
Nature of the Business	1. Nature of the Business
	Achillion Pharmaceuticals, Inc. (the “Company”) was incorporated on August 17, 1998 in Delaware. The Company is seeking to transform innovation into novel treatments that address the needs of patients by discovering and developing small molecule therapeutics for the treatment of infectious diseases and immune system disorders. The Company is devoting substantially all of its efforts towards product research and development.
	The Company incurred losses of $456,083 from inception through March 31, 2015 and had an accumulated deficit of $469,945 at March 31, 2015, which includes preferred stock dividends recognized until the Company’s initial public offering in 2006. The Company has funded its operations primarily through the sale of equity securities.
	Based on the Company’s current clinical plan, the Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to meet its current projected operating requirements for at least the next 12 months. However, the Company’s future capital requirements may change and will depend upon numerous factors, including but not limited to:
		•	the costs involved in the clinical development, manufacturing and formulation of ACH-3102, ACH-3422 and sovaprevir;
		•	the costs involved in the preclinical and planned clinical development of certain complement inhibitors;
		•	the scope of and costs associated with entering into cooperative study arrangements or licensing arrangements, if any, for the collaborative development of the Company’s drug candidates in combination with others’ drug candidates;
		•	the costs involved in obtaining regulatory approvals for the Company’s drug candidates;
		•	the scope, prioritization and number of programs the Company pursues;
		•	the costs involved in preparing, filing, prosecuting, maintaining, enforcing and defending patent and other intellectual property claims;
		•	the Company’s ability to raise incremental debt or equity capital, including any changes in the credit or equity markets that may impact its ability to obtain capital in the future;
		•	the costs associated with, and the outcome of, lawsuits against the Company, if any;
		•	the Company’s acquisition and development of new technologies and drug candidates; and
		•	competing technological and market developments currently unknown to the Company.

Accounting_Standards_Updates

Accounting Standards Updates	3 Months Ended
	Mar. 31, 2015
Accounting Standards Updates	2. Accounting Standards Updates
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. ASU No. 2014-09 requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. ASU No. 2014-09 will be effective on January 1, 2018. The Company does not believe ASU No. 2014-09 will have a material effect on its financial position and results of operations.
	In August 2014, FASB issued ASU No. 2014-15, “Presentation of Financial Statements – Going Concern.” ASU No. 2014-15 provides guidance regarding management’s responsibility to evaluate whether there exists substantial doubt about an organization’s ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. ASU No. 2014-15 is effective for annual reporting periods beginning after December 15, 2016, and interim periods thereafter. The Company does not believe ASU No. 2014-15 will have a material effect on its financial position and results of operations.
	In April 2015, FASB issued ASU No. 2015-03, “Interest – Imputation of Interest.” ASU No. 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015 (and interim periods within those fiscal years) with early adoption permitted and retrospective application required. The Company does not believe ASU No. 2015-03 will have a material effect on its financial position and results of operations.

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Basis of Presentation	3. Basis of Presentation
	The accompanying unaudited financial statements of the Company should be read in conjunction with the audited financial statements and notes as of and for the year ended December 31, 2014 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 5, 2015. The accompanying financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information, in accordance with the instructions to Form 10-Q and the guidance in Article 10 of Regulation S-X. Accordingly, since they are interim financial statements, the accompanying financial statements do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. The accompanying financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of management, necessary for a fair statement of the results of operations for the interim periods presented. Interim results are not necessarily indicative of results for a full year.
	The preparation of financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements and notes thereto. A discussion of the Company’s critical accounting policies and management estimates is described in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in Part I, Item II of this Quarterly Report on Form 10-Q.

Financing_Activities

Financing Activities	3 Months Ended
	Mar. 31, 2015
Financing Activities	4. Financing Activities
	Public Offering
	In February 2015, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with Leerink Partners LLC and Deutsche Bank Securities Inc., as representatives of the several underwriters named therein (collectively, the “Underwriters”), relating to a public offering of shares of the Company’s common stock, par value $0.001 per share, at a price of $10.25 per share less underwriting discounts and commissions (the “Offering”). The Company issued and sold to the Underwriters an aggregate of 13,800 shares of common stock in connection with the Offering. The Offering resulted in net proceeds to the Company of $132,558.

Earnings_Loss_Per_Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2015
Earnings (Loss) Per Share	5. Earnings (Loss) Per Share
	Basic earnings (loss) per share (“EPS”) is calculated in accordance with Accounting Standards Codification (“ASC”) 260, Earnings Per Share, by dividing net income or loss attributable to common stockholders by the weighted average common stock outstanding. Diluted EPS is calculated by adjusting weighted average common shares outstanding for the dilutive effect of common stock options and warrants. In periods in which a net loss is recorded, no effect is given to potentially dilutive securities, since the effect would be antidilutive. Securities that could potentially dilute basic EPS in the future were not included in the computation of diluted EPS because to do so would have been antidilutive. The calculations of basic and diluted net loss per share are as follows:
		Three Months Ended March 31,
		2015			2014
		(in thousands)
	Net loss (numerator)	$	(19,263	)	$	(16,088	)
	Weighted-average shares, in thousands (denominator)		111,202			96,792
	Basic and diluted net loss per share	$	(0.17	)	$	(0.17	)
	Potentially dilutive securities outstanding as of March 31, 2015 and 2014 are as follows:
		March 31,
		2015			2014
		(in thousands)
	Stock Options		9,148			9,172
	Warrants		2,833			5,338
	Total potentially dilutive securities outstanding		11,981			14,510

Collaboration_Arrangements

Collaboration Arrangements	3 Months Ended
	Mar. 31, 2015
Collaboration Arrangements	6. Collaboration Arrangements
	GCA Therapeutics, Ltd.
	In February 2010, the Company entered into a license agreement (the “Agreement”) with GCA Therapeutics, Ltd. (“GCAT”) for elvucitabine, the Company’s nucleoside reverse transcriptase inhibitor for the treatment of both hepatitis B virus infection and human immunodeficiency virus infection. The Agreement was amended and restated in March 2010. The exclusive license grants GCAT the right, through a Chinese joint venture with Tianjing Institute of Pharmaceutical Research, to clinically develop and commercialize elvucitabine in mainland China, Hong Kong and Taiwan.
	Under the terms of the Agreement, GCAT, through a sublicense agreement with a Chinese joint venture, T&T Pharma Co., Ltd., will assume all development and regulatory responsibility and associated costs for elvucitabine. The Company did not receive any payment upon the signing of the agreement. Upon the first commercial sale of a licensed product GCAT is obligated to pay $100 to the Company. Further, the Company will be eligible to receive royalties up to 15% of net sales in those territories.
	The Company does not believe that the milestone specified under the Agreement is substantive as achievement of the milestone is based solely on the performance of GCAT and does not relate to any past or future performance by the Company. Because the Company has no performance obligations under the Agreement, it intends to recognize revenue related to the milestone payment upon achievement of the milestone by GCAT. However, there can be no assurance that GCAT will achieve the milestone or that the Company will receive the related revenue. This Agreement shall be effective, unless earlier terminated, until the expiration of the last to expire royalty term.
	Ora, Inc.
	In October 2012, the Company entered into a license and development agreement (the “Ora Agreement”) with Ora, Inc. (“Ora”) for the worldwide development and commercialization of ACH-702 delivered topically or locally. The Ora Agreement was amended in April 2013. Under the terms of the Ora Agreement, Ora has assumed development and regulatory responsibility and associated costs for ACH-702. Upon initiation of the agreement, the Company received a one-time license fee of $100, which was recognized as revenue upon the completion of the technology transfer by the Company. The Company is eligible to receive up to $4,000 in development milestones and up to $7,000 in commercialization milestones as well as royalties up to 3.5% of net sales. The Company has no further obligations under the Ora Agreement.
	The Ora Agreement includes the right to sublicense any or all of the licensed rights, subject to the Company’s approval. Ora has agreed to pay the Company 15% of all up-front licensing payments and any other payment allocated to or received by Ora pursuant to any sublicense agreement granted by Ora under the Ora Agreement; provided that such payment is not a royalty on net sales and not a development or commercial milestone already due to Achillion. In December 2012, Ora entered into a sublicense agreement with Taejoon Pharmaceutical Co. for the development of ACH-702.
	The Company does not believe that the milestones specified under the Ora Agreement are substantive as achievement of the milestones is based solely on the performance of Ora and its sublicensee(s) and does not relate to any past or future performance by the Company. Because the Company has no performance obligations under the Ora Agreement, it intends to recognize revenue related to any milestone payments upon achievement of the milestone by Ora or its sublicensee(s). The Ora Agreement shall be effective and, unless earlier terminated, will continue until the last sale of each and every licensed product to an unrelated third party by Ora, its affiliate or sublicensee.

Marketable_Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2015
Marketable Securities	7. Marketable Securities
	The Company applies the provisions of Accounting Standards Codification (“ASC”) 820, Fair Value Measurements and Disclosures, for financial assets and liabilities measured on a recurring basis which requires disclosure that establishes a framework for measuring fair value and expands disclosures in the financial statements. The guidance requires that fair value measurements be classified and disclosed in one of the three categories:
	Level 1: Quoted prices in active markets for identical assets and liabilities that the reporting entity has the ability to access at the measurement date;
	Level 2: Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; or
	Level 3: Unobservable inputs.
	The fair value of the Company’s marketable securities of $228,432 and $79,215 as of March 31, 2015 and December 31, 2014, respectively, is valued based on level 2 inputs. The Company’s investments consist mainly of U.S. government and agency securities, government sponsored bond obligations and certain other corporate debt securities. Fair value is determined by taking into consideration valuations obtained from third-party pricing services. The third-party pricing services utilize industry standard valuation models, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities; issuer credit spreads; benchmark securities; and other observable inputs. The Company has assessed these as level 2 within the fair value hierarchy of ASC 820. The Company classifies its entire investment portfolio as available for sale as defined in ASC 320, Debt and Equity Securities. Securities are carried at fair value with the unrealized gains (losses) reported as a separate component of stockholders’ equity within accumulated other comprehensive income.
	The unrealized gain (loss) from marketable securities was $48 and $(12) at March 31, 2015 and December 31, 2014, respectively.
	As of March 31, 2015 and December 31, 2014, none of the Company’s investments were determined to be other than temporarily impaired.
	The following table summarizes the Company’s investments:
		March 31, 2015									December 31, 2014
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	69,341	$	73		—		$	69,414	$	4,747	$	3		—		$	4,750
	Corporate Debt Securities		142,928		21		(44	)		142,905		58,452		1		(16	)		58,437
	Government and Agency Securities		16,115		—		(2	)		16,113		16,028		1		(1	)		16,028
	Total	$	228,384	$	94		(46	)	$	228,432	$	79,227	$	5		(17	)	$	79,215

Accrued_Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2015
Accrued Expenses	8. Accrued Expenses
	Accrued expenses consist of the following:
		March 31, 2015		December 31, 2014
	Accrued compensation	$	1,971	$	846
	Accrued research and development expenses		2,044		4,727
	Accrued professional expenses		489		649
	Other accrued expenses		282		224
	Total	$	4,786	$	6,446
	Accrued research and development expenses are comprised of amounts owed to third-party contract research organizations, clinical investigators, laboratories and data managers for research and development work performed on behalf of the Company.

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt	9. Debt
	Debt consists of the following:
		March 31, 2015			December 31, 2014
	2011 Credit Facility, payable in monthly installments as notes mature through March 2015, with interest of 6.44% per annum	$	—		$	56
	2014 Credit Facility, payable in equal monthly installments through March 2018, with fixed interest of 6.20% to 6.30% per annum	$	613		$	418
	Total debt		613			474
	Less: current portion		(213	)		(195	)
	Total long-term debt, net of current portion	$	400		$	279
	In March 2011, the Company entered into a Master Security Agreement for a $2,000 Capital Expenditure Line of Credit, (the “2011 Credit Facility”) with Webster Bank (“Webster”). Under the 2011 Credit Facility, the Company could draw down equipment loan advances for the purchase of new laboratory equipment through March 2013. In connection with the Master Security Agreement, the Company granted Webster a security interest in equipment to be purchased under the Credit Facility
	In October 2014, the Company entered into a Master Security Agreement for a $1,000 Capital Expenditure Line of Credit (the “2014 Credit Facility”) with Webster. Under the 2014 Credit Facility, the Company can draw down equipment loan advances for the purchase of new laboratory equipment through October 2015. In connection with the Master Security Agreement, the Company granted Webster a security interest in equipment to be purchased under the Credit Facility. In October 2014 and March 2015, Webster advanced $440 and $229, respectively, to the Company under the Credit Facility.
	The fair value for this debt is classified as a level 2 measurement. Fair value is computed using a discounted cash flow model based on current interest rates. At this time, the carrying value approximates fair value.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
Stock-Based Compensation	10. Stock-Based Compensation
	The Company’s 2006 Stock Incentive Plan, as amended, (the “2006 Plan”), is administered by the Company’s Board of Directors and provides for the grant of incentive stock options, nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights and other stock-based awards. The Company’s officers, employees, consultants, advisors and directors are eligible to receive awards under the 2006 Plan; however, incentive stock options may only be granted to employees. Stock option awards are exercisable for a period determined by the Company, but in no event longer than ten years from the date of the grant. Stock option awards generally vest ratably over four years. There were 1,905 shares available to be granted under the 2006 Plan as of March 31, 2015.
	A summary of the status of the Company’s stock option activity for the three months ended March 31, 2015 is presented in the table and narrative below:
		Options			Weighted
					Average
					Exercise
					Price
	Outstanding at January 1, 2015		9,493		$	6.88
	Granted		5			11.44
	Exercised		(156	)		3.39
	Forfeited		(194	)		7.73
	Cancelled		—			—
	Outstanding at March 31, 2015		9,148		$	6.92
	Options exercisable at March 31, 2015		5,106		$	5.84
	Weighted-average fair value of options granted during the period				$	8.66
	The Company utilizes the Black-Scholes option pricing model for determining the estimated fair value for stock-based awards. The Black-Scholes model requires the use of assumptions which determine the fair value of the stock-based awards. The assumptions used to value options granted are as follows:
		For the Three Months Ended
		March 31, 2015			March 31, 2014
	Expected term of option		6.25 years			5.0 - 6.1 years
	Expected volatility		91	%		92	%
	Risk free interest rate		1.54	%		2.02	%
	Expected dividend yield		0	%		0	%
	Total compensation expense recorded in the accompanying statements of operations associated with stock option grants made to employees was $2,864 and $1,508 for the three months ended March 31, 2015 and 2014, respectively. The Company recorded no tax benefit related to these stock options since the Company currently maintains a full valuation allowance on its deferred tax assets.
	As of March 31, 2015, the intrinsic value of the stock options outstanding was $34,242, of which $22,443 related to vested stock options and $11,799 related to unvested stock options. The intrinsic value of stock options is calculated based on the difference between the exercise prices of the underlying common stock and the quoted stock price of the Company’s common stock as of the reporting date.
	As of March 31, 2015, the total compensation cost related to unvested stock options not yet recognized in the financial statements is approximately $20,942, net of estimated forfeitures, and the weighted average period over which this amount is expected to be recognized is 1.6 years.

Comprehensive_Loss

Comprehensive Loss	3 Months Ended
	Mar. 31, 2015
Comprehensive Loss	11. Comprehensive Loss
	The Company reports and presents comprehensive loss in accordance with ASC 220, Comprehensive Income, which establishes standards for reporting and display of comprehensive loss and its components in a full set of general purpose financial statements. The objective of the statement is to report a measure of all changes in equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners (comprehensive loss). The Company’s other comprehensive gain arises from net unrealized gains on marketable securities and was immaterial for all periods presented.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Stockholders' Equity	12. Stockholders’ Equity
	Changes in stockholders’ equity for the three months ended March 31, 2015 and 2014 were as follows:
		For the Three Months Ended March 31,
		2015			2014
	Balance at December 31, 2014 and 2013	$	143,469		$	152,958
	Net loss		(19,263	)		(16,088	)
	Stock based compensation		2,917			1,556
	Exercise of stock options		527			5
	Change in unrealized gain on marketable securities		60			18
	Issuance of common stock		138,291			—
	Balance at March 31, 2015 and 2014	$	266,001		$	138,449

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies	13. Commitments and Contingencies
	From time to time, in the ordinary course of business, the Company is subject to litigation and regulatory examinations as well as information gathering requests, inquiries and investigations.

Earnings_Loss_Per_Share_Tables

Earnings (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Calculations of Basic and Diluted Net Loss per Share	The calculations of basic and diluted net loss per share are as follows:
		Three Months Ended March 31,
		2015			2014
		(in thousands)
	Net loss (numerator)	$	(19,263	)	$	(16,088	)
	Weighted-average shares, in thousands (denominator)		111,202			96,792
	Basic and diluted net loss per share	$	(0.17	)	$	(0.17	)
Potentially Dilutive Securities Outstanding	Potentially dilutive securities outstanding as of March 31, 2015 and 2014 are as follows:
		March 31,
		2015			2014
		(in thousands)
	Stock Options		9,148			9,172
	Warrants		2,833			5,338
	Total potentially dilutive securities outstanding		11,981			14,510

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Summary of the Investments	The following table summarizes the Company’s investments:
		March 31, 2015									December 31, 2014
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	69,341	$	73		—		$	69,414	$	4,747	$	3		—		$	4,750
	Corporate Debt Securities		142,928		21		(44	)		142,905		58,452		1		(16	)		58,437
	Government and Agency Securities		16,115		—		(2	)		16,113		16,028		1		(1	)		16,028
	Total	$	228,384	$	94		(46	)	$	228,432	$	79,227	$	5		(17	)	$	79,215

Accrued_Expenses_Tables

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2015
Summary of Accrued Expenses	Accrued expenses consist of the following:
		March 31, 2015		December 31, 2014
	Accrued compensation	$	1,971	$	846
	Accrued research and development expenses		2,044		4,727
	Accrued professional expenses		489		649
	Other accrued expenses		282		224
	Total	$	4,786	$	6,446

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Schedule of Debt	Debt consists of the following:
		March 31, 2015			December 31, 2014
	2011 Credit Facility, payable in monthly installments as notes mature through March 2015, with interest of 6.44% per annum	$	—		$	56
	2014 Credit Facility, payable in equal monthly installments through March 2018, with fixed interest of 6.20% to 6.30% per annum	$	613		$	418
	Total debt		613			474
	Less: current portion		(213	)		(195	)
	Total long-term debt, net of current portion	$	400		$	279

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Summary of Stock Option Activity	A summary of the status of the Company’s stock option activity for the three months ended March 31, 2015 is presented in the table and narrative below:
		Options			Weighted
					Average
					Exercise
					Price
	Outstanding at January 1, 2015		9,493		$	6.88
	Granted		5			11.44
	Exercised		(156	)		3.39
	Forfeited		(194	)		7.73
	Cancelled		—			—
	Outstanding at March 31, 2015		9,148		$	6.92
	Options exercisable at March 31, 2015		5,106		$	5.84
	Weighted-average fair value of options granted during the period				$	8.66
Assumptions Used to Value Options Granted	The assumptions used to value options granted are as follows:
		For the Three Months Ended
		March 31, 2015			March 31, 2014
	Expected term of option		6.25 years			5.0 - 6.1 years
	Expected volatility		91	%		92	%
	Risk free interest rate		1.54	%		2.02	%
	Expected dividend yield		0	%		0	%

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Changes in Stockholders' Equity	Changes in stockholders’ equity for the three months ended March 31, 2015 and 2014 were as follows:
		For the Three Months Ended March 31,
		2015			2014
	Balance at December 31, 2014 and 2013	$	143,469		$	152,958
	Net loss		(19,263	)		(16,088	)
	Stock based compensation		2,917			1,556
	Exercise of stock options		527			5
	Change in unrealized gain on marketable securities		60			18
	Issuance of common stock		138,291			—
	Balance at March 31, 2015 and 2014	$	266,001		$	138,449

Nature_of_Business_Additional_

Nature of Business - Additional Information (Detail) (USD $)	3 Months Ended		199 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014
Nature Of Business [Line Items]
Losses incurred from inception	($19,263)	($16,088)	($456,083)
Accumulated deficit	($469,945)		($469,945)	($450,682)

Financing_Activities_Additiona

Financing Activities - Additional Information (Detail) (USD $)	3 Months Ended	1 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Feb. 28, 2015	Dec. 31, 2014
Financing Activities [Line Items]
Common stock, par value	$0.00		$0.00
Proceeds from issuance of common stock	$138,291
Public Offering
Financing Activities [Line Items]
Common stock, par value		$0.00
Share price		$10.25
Number of common shares issued in public or private offering		13,800
Proceeds from issuance of common stock		$132,558

Calculations_of_Basic_and_Dilu

Calculations of Basic and Diluted Net Loss per Share (Detail) (USD $)	3 Months Ended		199 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]
Net loss (numerator)	($19,263)	($16,088)	($456,083)
Weighted-average shares, in thousands (denominator)	111,202	96,792
Basic and diluted net loss per share	($0.17)	($0.17)

Potentially_Dilutive_Securitie

Potentially Dilutive Securities Outstanding (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	11,981	14,510
Stock incentive plans
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	9,148	9,172
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	2,833	5,338

Collaboration_Arrangements_Add

Collaboration Arrangements - Additional Information (Detail) (USD $)	3 Months Ended	1 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Oct. 31, 2012
GCA Therapeutics
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone revenue	100
GCA Therapeutics | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty receivable on net sales	15.00%
Ora Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License revenue		100
Percentage of up front sub license fees		15.00%
Ora Agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty receivable on net sales		3.50%
Ora Agreement | Maximum | Development Milestone
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone revenue		4,000
Ora Agreement | Maximum | Commercialization Milestones
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Future milestone revenue		$7,000

Marketable_Securities_Addition

Marketable Securities - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Fair value of marketable securities	$228,432	$79,215
Unrealized (loss) gain on marketable securities	48	-12
Fair Value, Inputs, Level 2
Schedule of Available-for-sale Securities [Line Items]
Fair value of marketable securities	$228,432	$79,215

Summary_of_Investments_Detail

Summary of Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$228,384	$79,227
Unrealized Gain	94	5
Unrealized (Loss)	-46	-17
Estimated Fair Value	228,432	79,215
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	69,341	4,747
Unrealized Gain	73	3
Estimated Fair Value	69,414	4,750
Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	142,928	58,452
Unrealized Gain	21	1
Unrealized (Loss)	-44	-16
Estimated Fair Value	142,905	58,437
Government and Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,115	16,028
Unrealized Gain		1
Unrealized (Loss)	-2	-1
Estimated Fair Value	$16,113	$16,028

Accrued_Expenses_Detail

Accrued Expenses (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Accrued Liabilities [Line Items]
Accrued compensation	$1,971	$846
Accrued research and development expenses	2,044	4,727
Accrued professional expenses	489	649
Other accrued expenses	282	224
Total	$4,786	$6,446

Debt_Detail

Debt (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Line of Credit Facility [Line Items]
Total debt	$613	$474
Less: current portion	-213	-195
Total long-term debt, net of current portion	400	279
2011 Credit Facility
Line of Credit Facility [Line Items]
Total debt		56
2014 Credit Facility
Line of Credit Facility [Line Items]
Total debt	$613	$418

Debt_Parenthetical_Detail

Debt (Parenthetical) (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
2011 Credit Facility
Line of Credit Facility [Line Items]
Credit Facility, interest rate	6.44%	6.44%
Debt instrument, maturity year	1-Mar-15	1-Mar-15
2014 Credit Facility
Line of Credit Facility [Line Items]
Credit Facility, interest rate minimum	6.20%	6.20%
Credit Facility, interest rate maximum	6.30%	6.30%
Debt instrument, maturity year	1-Mar-18	1-Mar-18

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)	3 Months Ended	1 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2015	Oct. 31, 2014	Mar. 31, 2011
2011 Credit Facility
Line of Credit Facility [Line Items]
Line of Credit Facility, maximum borrowing capacity				$2,000
Line of Credit Facility, expiration date	31-Mar-13
2014 Credit Facility
Line of Credit Facility [Line Items]
Line of Credit Facility, maximum borrowing capacity			1,000
Line of Credit Facility, expiration date	31-Oct-15
Line of Credit Facility advance drawn		$229	$440

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of stock options outstanding	$34,242
Intrinsic value of stock options vested	22,443
Intrinsic value of stock options unvested	11,799
Total compensation cost related to unvested stock options not yet recognized	20,942
Total compensation cost related to stock options not yet recognized, Weighted average period for recognition	1 year 7 months 6 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense associated	$2,864	$1,508
2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock available for grant	1,905
2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested period	4 years
2006 Stock Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercisable period	10 years

Companys_Stock_Option_Activity

Company's Stock Option Activity (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015
Options
Outstanding at January 1, 2015	9,493
Stock Options, Granted	5
Stock Options, Exercised	-156
Stock Options, Forfeited	-194
Stock Options, Cancelled	0
Outstanding at March 31, 2015	9,148
Options exercisable at March 31, 2015	5,106
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding at January 1, 2015	$6.88
Weighted Average Exercise Price, Granted	$11.44
Weighted Average Exercise Price, Exercised	$3.39
Weighted Average Exercise Price, Forfeited	$7.73
Weighted Average Exercise Price, Cancelled	$0
Weighted Average Exercise Price, Outstanding at March 31, 2015	$6.92
Weighted Average Exercise Price, Options exercisable at March 31, 2015	$5.84
Weighted Average Exercise Price, Weighted-average fair value of options granted during the period	$8.66

Assumptions_Used_to_Value_Opti

Assumptions Used to Value Options Granted (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	91.00%	92.00%
Risk free interest rate	1.54%	2.02%
Expected dividend yield	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of option	6 years 3 months	5 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of option		6 years 1 month 6 days

Changes_in_Stockholders_Equity

Changes in Stockholders' Equity (Detail) (USD $)	3 Months Ended		199 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015
Stockholders Equity [Line Items]
Balance at December 31, 2014 and 2013	$143,469	$152,958
Net loss	-19,263	-16,088	-456,083
Stock based compensation	2,917	1,556
Exercise of stock options	527	5
Change in unrealized gain on marketable securities	60	18
Issuance of common stock	138,291
Balance at March 31, 2015 and 2014	$266,001	$138,449	$266,001