Achillion Pharmaceuticals 10-Q 7 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Aug. 01, 2014
Document Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Trading Symbol	'ACHN	'
Entity Registrant Name	'ACHILLION PHARMACEUTICALS INC	'
Entity Central Index Key	'0001070336	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	97,788,046

Balance_Sheets

Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$33,268	$33,457
Marketable securities	98,205	88,393
Accounts and other receivables	194	480
Prepaid expenses and other current assets	1,923	2,452
Total current assets	133,590	124,782
Marketable securities	'	36,139
Fixed assets, net	1,279	1,265
Deferred financing costs	161	79
Restricted cash	152	152
Total assets	135,182	162,417
Current liabilities:	'	'
Accounts payable	2,004	4,591
Accrued expenses	7,039	4,521
Current portion of long-term debt	164	291
Total current liabilities	9,207	9,403
Long-term debt	'	56
Total liabilities	9,207	9,459
Commitments and contingencies (Note 12)	'	'
Stockholders' Equity:	'	'
Common Stock, $.001 par value; 200,000 shares authorized: 97,787 and 96,792 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	98	97
Additional paid-in capital	539,271	534,529
Accumulated deficit	-413,419	-381,674
Accumulated other comprehensive income	25	6
Total stockholders' equity	125,975	152,958
Total liabilities and stockholders' equity	$135,182	$162,417

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
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	97,787	96,792
Common Stock, shares outstanding	97,787	96,792

Statements_of_Comprehensive_Lo

Statements of Comprehensive Loss (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue	$0	$0	$0	$0
Operating expenses	'	'	'	'
Research and development	12,177	16,568	25,019	25,288
General and administrative	3,589	3,545	6,982	6,619
Total operating expenses	15,766	20,113	32,001	31,907
Loss from operations	-15,766	-20,113	-32,001	-31,907
Other income (expense)	'	'	'	'
Interest income	117	185	275	263
Interest expense	-8	-12	-19	-34
Net loss	-15,657	-19,940	-31,745	-31,678
Total comprehensive loss (Note 10)	($15,656)	($20,051)	($31,726)	($31,838)
Basic and diluted net loss per share (Note 4)	($0.16)	($0.21)	($0.33)	($0.35)
Weighted average number of shares used in computing basic and diluted net loss per share	97,017	96,580	96,905	91,245

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities	'	'
Net loss	($31,745)	($31,678)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation	232	197
Non-cash stock-based compensation	3,197	3,087
Premium on purchases of marketable securities	-724	-3,077
Amortization of premium on marketable securities	1,128	956
Changes in operating assets and liabilities:	'	'
Accounts and other receivables	286	-332
Prepaid expenses and other assets	529	-271
Accounts payable	-2,587	2,285
Accrued expenses	2,518	2,422
Net cash used in operating activities	-27,166	-26,411
Cash flows from investing activities	'	'
Purchases of fixed assets	-246	-238
Purchases of marketable securities	-55,027	-144,947
Maturities of marketable securities	80,969	36,865
Net cash provided by (used in) investing activities	25,696	-108,320
Cash flows from financing activities	'	'
Proceeds from sale of common stock, net of issuance costs	'	133,211
Proceeds from exercise of stock options	1,450	298
Proceeds from sale of common stock under Employee Stock Purchase Plan	96	105
Payment of deferred financing costs	-82	'
Repayments of debt	-183	-172
Net cash provided by financing activities	1,281	133,442
Net increase in cash and cash equivalents	-189	-1,289
Cash and cash equivalents, beginning of period	33,457	18,526
Cash and cash equivalents, end of period	33,268	17,237
Supplemental disclosure of cash flow information	'	'
Cash paid for interest	20	27
Supplemental disclosure of non-cash financing activities	'	'
Cashless exercise of warrants	$2,848	'

Nature_of_the_Business

Nature of the Business	6 Months Ended
	Jun. 30, 2014
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 discover, develop and commercialize innovative drug therapies. The Company is devoting substantially all of its efforts towards product research and development.
	The Company incurred losses of $399,557 from inception through June 30, 2014 and had an accumulated deficit of $413,419 at June 30, 2014, 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.
	The Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to meet its projected operating requirements through at least June 30, 2015. 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-3422, ACH-3102 and sovaprevir;
		•	the scope of and costs associated with entering into cooperative study arrangements, CSAs, if any, for the collaborative development of its 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.
	In June 2013, the U.S. Food and Drug Administration (the “FDA”) placed a clinical hold on sovaprevir after elevations in liver enzymes were noted in a phase I healthy subjects drug-drug interaction study evaluating the effects of concomitant administration of sovaprevir with ritonavir-boosted atazanavir. In June 2014, the FDA removed the clinical hold on sovaprevir, allowing the Company to conduct therapeutic trials of sovaprevir in HCV patients with a maximum dose of 200 mg once daily and in single dose studies in healthy volunteers, but the FDA maintained a partial clinical hold on sovaprevir for multiple dose studies that the Company may conduct in healthy volunteers. The Company expects to continue to work collaboratively with the FDA on the continued clinical development of sovaprevir. Following an internal assessment of the Company’s protease inhibitor drug candidates, sovaprevir and ACH-2684, the Company has determined to advance sovaprevir in future clinical trials with ACH-3422 and ACH-3102, rather than ACH-2684.

Accounting_Standards_Updates

Accounting Standards Updates	6 Months Ended
	Jun. 30, 2014
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”. The objective of ASU 2014-19 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle of the new standard is that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard is effective for annual reporting periods beginning after December 15, 2016 and allows for prospective or retrospective application. The Company does not believe this pronouncement will have a material effect on its financial statements.

Basis_of_Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2014
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, 2013 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 7, 2014. 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.

Earnings_Loss_Per_Share_EPS

Earnings (Loss) Per Share ("EPS")	6 Months Ended
	Jun. 30, 2014
Earnings (Loss) Per Share ("EPS")	'
	4. Earnings (Loss) Per Share (“EPS”)
	Basic EPS is calculated in accordance with 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:
		Six Months Ended June 30,
		2014			2013
		(in thousands)
	Net loss (numerator)	$	(31,745	)	$	(31,678	)
	Weighted-average shares, in thousands (denominator)		96,905			91,245
	Basic and diluted net loss per share	$	(0.33	)	$	(0.35	)
	Potentially dilutive securities outstanding as of June 30, 2014 and 2013 are as follows:
		June 30,
		2014			2013
		(in thousands)
	Stock options		8,603			7,902
	Warrants		4,531			5,348
	Total potentially dilutive securities outstanding		13,134			13,250

Collaboration_Arrangements

Collaboration Arrangements	6 Months Ended
	Jun. 30, 2014
Collaboration Arrangements	'
	5. 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 (“HBV”) infection and human immunodeficiency virus (“HIV”) 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	6 Months Ended
	Jun. 30, 2014
Marketable Securities	'
	6. 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 $98,205 and $124,532 as of June 30, 2014 and December 31, 2013, 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 from marketable securities was $25 and $6 at June 30, 2014 and December 31, 2013, respectively.
	As of June 30, 2014 and December 31, 2013, none of the Company’s investments were determined to be other than temporarily impaired.
	The following table summarizes the Company’s investments:
		June 30, 2014									December 31, 2013
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	8,037	$	11		—		$	8,048	$	14,190	$	9		—		$	14,199
	Corporate Debt Securities		77,166		24		(17	)		77,173		95,036		27		(25	)		95,038
	Government and Agency Securities		12,977		7		—			12,984		15,300		1		(6	)		15,295
	Total	$	98,180	$	42		(17	)	$	98,205	$	124,526	$	37		(31	)	$	124,532
	The following table summarizes the contractual maturities of the Company’s investments:
		June 30, 2014		December 31, 2013
	Mature in less than one year	$	98,205	$	88,393
	Mature in one to five years		—		36,139
	Total	$	98,205	$	124,532

Accrued_Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2014
Accrued Expenses	'
	7. Accrued Expenses
	Accrued expenses consist of the following:
		June 30, 2014		December 31, 2013
	Accrued compensation	$	1,864	$	554
	Accrued research and development expenses		4,264		3,276
	Accrued professional expenses		686		432
	Other accrued expenses		225		259
	Total	$	7,039	$	4,521
	Accrued research and development expenses are comprised of amounts owed to third-party contract research organizations, or “CROs”, clinical investigators, laboratories and data managers for research and development work performed on behalf of the Company.

Debt

Debt	6 Months Ended
	Jun. 30, 2014
Debt	'
	8. Debt
	Debt consists of the following:
		June 30, 2014			December 31, 2013
	2011 Credit Facility, payable in monthly installments through March 2015, with interest of 6.44% to 6.79% per annum	$	164		$	347
	Total debt		164			347
	Less: current portion		(164	)		(291	)
	Total long-term debt, net of current portion	$	—		$	56
	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. Under the 2011 Credit Facility, the Company could draw down equipment loan advances for the purchase of new laboratory equipment through March 2013. The purchased equipment serves as collateral for the 2011 Credit Facility. The fair value for this debt would be classified as a level 2 measurement due to the use of inputs based on similar liabilities in the market. At this time, the carrying value approximates fair value.

StockBased_Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2014
Stock-Based Compensation	'
	9. Stock-Based Compensation
	The Company’s 2006 Stock Incentive Plan, or 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 options granted are exercisable for a period determined by the Company, but in no event longer than ten years from the date of the grant. Stock options generally vest ratably over four years. There were 3,430 shares available to be granted under the 2006 Plan as of June 30, 2014.
	A summary of the status of the Company’s stock option activity for the six months ended June 30, 2014 is presented in the table and narrative below:
		Stock			Weighted
		Options			Average
					Exercise
					Price
	Outstanding at January 1, 2014		9,083		$	5.14
	Granted		510			3.28
	Exercised		(541	)		2.68
	Forfeited		(326	)		3.48
	Cancelled		(123	)		5.2
	Outstanding at June 30, 2014		8,603		$	5.25
	Options exercisable at June 30, 2014		4,520		$	5.41
	Weighted-average fair value of options granted during the period				$	2.39
	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 stock options granted are as follows:
		For the Six Months Ended
		June 30, 2014			June 30, 2013
	Expected term of option		5.0 - 6.1 years			5.0 - 6.1 years
	Expected volatility		92 - 96	%		87 - 88	%
	Risk free interest rate		1.88 - 2.02	%		1.01 - 1.69	%
	Expected dividend yield		0	%		0	%
	Total compensation expense recorded in the accompanying statements of operations associated with option grants made to employees was $3,160 and $2,978 for the six months ended June 30, 2014 and 2013, 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 June 30, 2014, the intrinsic value of the stock options outstanding was $23,628, of which $12,650 related to vested stock options and $10,978 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 June 30, 2014.
	As of June 30, 2014, the total compensation cost related to unvested stock options not yet recognized in the financial statements is approximately $12,472, net of estimated forfeitures, and the weighted average period over which this amount is expected to be recognized is 1.4 years.

Comprehensive_Loss

Comprehensive Loss	6 Months Ended
	Jun. 30, 2014
Comprehensive Loss	'
	10. 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 loss arises from net unrealized losses on marketable securities and was immaterial for all periods presented.

Stockholders_Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2014
Stockholders' Equity	'
	11. Stockholders’ Equity
	Changes in stockholders’ equity for the six months ended June 30, 2014 and 2013 were as follows:
		For the Six Months Ended June 30,
		2014			2013
	Balance at December 31, 2013 and 2012	$	152,958		$	72,047
	Net loss		(31,745	)		(31,678	)
	Stock-based compensation		3,197			3,087
	Exercise of stock options		1,450			298
	Change in unrealized loss on marketable securities		19			(160	)
	Issuance of common stock		—			133,211
	Issuance of common stock under the Employee Stock Purchase Plan		96			105
	Balance at June 30, 2014 and 2013	$	125,975		$	176,910

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies	'
	12. 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.
	On May 5, 2014, the lead plaintiffs in the previously disclosed consolidated class action lawsuit originally filed in October 2013 against the Company and certain of its current and former officers in the United States District Court for the District of Connecticut voluntarily dismissed all of their claims without prejudice. The Court approved the volunatry dismissal and closed the case on May 6, 2014. A dismissal without prejudice does not prevent the litigation of the same claims in a subsequent action.

Earnings_Loss_Per_Share_EPS_Ta

Earnings (Loss) Per Share ("EPS") (Tables)	6 Months Ended
	Jun. 30, 2014
Calculations of Basic and Diluted Net Loss per Share	'
	The calculations of basic and diluted net loss per share are as follows:
		Six Months Ended June 30,
		2014			2013
		(in thousands)
	Net loss (numerator)	$	(31,745	)	$	(31,678	)
	Weighted-average shares, in thousands (denominator)		96,905			91,245
	Basic and diluted net loss per share	$	(0.33	)	$	(0.35	)
Potentially Dilutive Securities Outstanding	'
	Potentially dilutive securities outstanding as of June 30, 2014 and 2013 are as follows:
		June 30,
		2014			2013
		(in thousands)
	Stock options		8,603			7,902
	Warrants		4,531			5,348
	Total potentially dilutive securities outstanding		13,134			13,250

Marketable_Securities_Tables

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2014
Summary of the Investments	'
	The following table summarizes the Company’s investments:
		June 30, 2014									December 31, 2013
		Amortized		Unrealized		Unrealized			Estimated		Amortized		Unrealized		Unrealized			Estimated
		Cost		Gain		(Loss)			Fair Value		Cost		Gain		(Loss)			Fair Value
	Commercial Paper	$	8,037	$	11		—		$	8,048	$	14,190	$	9		—		$	14,199
	Corporate Debt Securities		77,166		24		(17	)		77,173		95,036		27		(25	)		95,038
	Government and Agency Securities		12,977		7		—			12,984		15,300		1		(6	)		15,295
	Total	$	98,180	$	42		(17	)	$	98,205	$	124,526	$	37		(31	)	$	124,532
Summary of Contractual Maturities of Investments	'
	The following table summarizes the contractual maturities of the Company’s investments:
		June 30, 2014		December 31, 2013
	Mature in less than one year	$	98,205	$	88,393
	Mature in one to five years		—		36,139
	Total	$	98,205	$	124,532

Accrued_Expenses_Tables

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2014
Summary of Accrued Expenses	'
	Accrued expenses consist of the following:
		June 30, 2014		December 31, 2013
	Accrued compensation	$	1,864	$	554
	Accrued research and development expenses		4,264		3,276
	Accrued professional expenses		686		432
	Other accrued expenses		225		259
	Total	$	7,039	$	4,521

Debt_Tables

Debt (Tables)	6 Months Ended
	Jun. 30, 2014
Schedule of Debt	'
	Debt consists of the following:
		June 30, 2014			December 31, 2013
	2011 Credit Facility, payable in monthly installments through March 2015, with interest of 6.44% to 6.79% per annum	$	164		$	347
	Total debt		164			347
	Less: current portion		(164	)		(291	)
	Total long-term debt, net of current portion	$	—		$	56

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2014
Summary of Stock Option Activity	'
	A summary of the status of the Company’s stock option activity for the six months ended June 30, 2014 is presented in the table and narrative below:
		Stock			Weighted
		Options			Average
					Exercise
					Price
	Outstanding at January 1, 2014		9,083		$	5.14
	Granted		510			3.28
	Exercised		(541	)		2.68
	Forfeited		(326	)		3.48
	Cancelled		(123	)		5.2
	Outstanding at June 30, 2014		8,603		$	5.25
	Options exercisable at June 30, 2014		4,520		$	5.41
	Weighted-average fair value of options granted during the period				$	2.39
Assumptions Used to Value Stock Options Granted	'
	The assumptions used to value stock options granted are as follows:
		For the Six Months Ended
		June 30, 2014			June 30, 2013
	Expected term of option		5.0 - 6.1 years			5.0 - 6.1 years
	Expected volatility		92 - 96	%		87 - 88	%
	Risk free interest rate		1.88 - 2.02	%		1.01 - 1.69	%
	Expected dividend yield		0	%		0	%

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2014
Changes in Stockholders' Equity	'
	Changes in stockholders’ equity for the six months ended June 30, 2014 and 2013 were as follows:
		For the Six Months Ended June 30,
		2014			2013
	Balance at December 31, 2013 and 2012	$	152,958		$	72,047
	Net loss		(31,745	)		(31,678	)
	Stock-based compensation		3,197			3,087
	Exercise of stock options		1,450			298
	Change in unrealized loss on marketable securities		19			(160	)
	Issuance of common stock		—			133,211
	Issuance of common stock under the Employee Stock Purchase Plan		96			105
	Balance at June 30, 2014 and 2013	$	125,975		$	176,910

Nature_of_Business_Additional_

Nature of Business - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		190 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013
Nature Of Business [Line Items]	'	'	'	'	'	'
Losses incurred from inception	($15,657)	($19,940)	($31,745)	($31,678)	($399,557)	'
Accumulated deficit	($413,419)	'	($413,419)	'	($413,419)	($381,674)

Calculations_of_Basic_and_Dilu

Calculations of Basic and Diluted Net Loss per Share (Detail) (USD $)	3 Months Ended		6 Months Ended		190 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014
Schedule Of Calculation Of Numerator And Denominator In Earnings Per Share [Line Items]	'	'	'	'	'
Net loss (numerator)	($15,657)	($19,940)	($31,745)	($31,678)	($399,557)
Weighted-average shares, in thousands (denominator)	97,017	96,580	96,905	91,245	'
Basic and diluted net loss per share	($0.16)	($0.21)	($0.33)	($0.35)	'

Potentially_Dilutive_Securitie

Potentially Dilutive Securities Outstanding (Detail)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	13,134	13,250
Stock options	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	8,603	7,902
Warrants	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Total potentially dilutive securities outstanding	4,531	5,348

Collaboration_Arrangements_Add

Collaboration Arrangements - Additional Information (Detail) (USD $)	6 Months Ended		12 Months Ended	1 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2012	Oct. 31, 2012	Oct. 30, 2012	Oct. 30, 2012
	Maximum	License	Ora Agreement	Ora Agreement	Ora Agreement	Ora Agreement
				Maximum	Development Milestone	Commercialization Milestones
					Maximum	Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'	'	'	'	'
Future milestone revenue	'	$100	'	'	$4,000	$7,000
Percentage of royalty receivable on net sales	15.00%	'	'	3.50%	'	'
License revenue	'	'	$100	'	'	'
Percentage of up front sub license fees	'	'	15.00%	'	'	'

Marketable_Securities_Addition

Marketable Securities - Additional Information (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value of marketable securities	$98,205	$124,532
Unrealized gain on marketable securities	25	6
Fair Value, Inputs, Level 2	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Fair value of marketable securities	$98,205	$124,532

Summary_of_Investments_Detail

Summary of Investments (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$98,180	$124,526
Unrealized Gain	42	37
Unrealized (Loss)	-17	-31
Estimated Fair Value	98,205	124,532
Commercial Paper	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	8,037	14,190
Unrealized Gain	11	9
Estimated Fair Value	8,048	14,199
Corporate Debt Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	77,166	95,036
Unrealized Gain	24	27
Unrealized (Loss)	-17	-25
Estimated Fair Value	77,173	95,038
Government and Agency Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	12,977	15,300
Unrealized Gain	7	1
Unrealized (Loss)	'	-6
Estimated Fair Value	$12,984	$15,295

Summary_of_Contractual_Maturit

Summary of Contractual Maturities of Investments (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Mature in less than one year	$98,205	$88,393
Mature in one to five years	'	36,139
Estimated Fair Value	$98,205	$124,532

Accrued_Expenses_Detail

Accrued Expenses (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Liabilities [Line Items]	'	'
Accrued compensation	$1,864	$554
Accrued research and development expenses	4,264	3,276
Accrued professional expenses	686	432
Other accrued expenses	225	259
Total	$7,039	$4,521

Debt_Detail

Debt (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Line of Credit Facility [Line Items]	'	'
Total debt	$164	$347
Less: current portion	-164	-291
Total long-term debt, net of current portion	'	56
Total debt	164	347
2011 Credit Facility	'	'
Line of Credit Facility [Line Items]	'	'
Total debt	164	347
Total debt	$164	$347

Debt_Parenthetical_Detail

Debt (Parenthetical) (Detail) (2011 Credit Facility)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
2011 Credit Facility	'	'
Line of Credit Facility [Line Items]	'	'
Credit Facility, interest rate minimum	6.44%	6.44%
Credit Facility, interest rate maximum	6.79%	6.79%
Debt instrument, maturity year	1-Mar-15	1-Mar-15

Debt_Additional_Information_De

Debt - Additional Information (Detail) (2011 Credit Facility, USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 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	'

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Intrinsic value of stock options outstanding	$23,628	'
Intrinsic value of stock options vested	12,650	'
Intrinsic value of stock options unvested	10,978	'
Total compensation cost related to unvested stock options not yet recognized	12,472	'
Total compensation cost related to stock options not yet recognized, Weighted average period for recognition	'1 year 4 months 24 days	'
Stock options	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Total compensation expense associated	$3,160	$2,978
2006 Stock Incentive Plan	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares of common stock available for grant	3,430	'
2006 Stock Incentive Plan | Stock options	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock options vested period	'4 years	'
2006 Stock Incentive Plan | Stock options | Maximum	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock options exercisable period	'10 years	'

Companys_Stock_Option_Activity

Company's Stock Option Activity (Detail) (USD $)	6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014
Options	'
Outstanding at January 1, 2014	9,083
Stock Options, Granted	510
Stock Options, Exercised	-541
Stock Options, Forfeited	-326
Stock Options, Cancelled	-123
Outstanding at June 30, 2014	8,603
Options exercisable at June 30, 2014	4,520
Weighted Average Exercise Price	'
Weighted Average Exercise Price, Outstanding at January 1, 2014	$5.14
Weighted Average Exercise Price, Granted	$3.28
Weighted Average Exercise Price, Exercised	$2.68
Weighted Average Exercise Price, Forfeited	$3.48
Weighted Average Exercise Price, Cancelled	$5.20
Weighted Average Exercise Price, Outstanding at June 30, 2014	$5.25
Weighted Average Exercise Price, Options exercisable at June 30, 2014	$5.41
Weighted Average Exercise Price, Weighted-average fair value of options granted during the period	$2.39

Assumptions_Used_to_Value_Stoc

Assumptions Used to Value Stock Options Granted (Detail)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected dividend yield	0.00%	0.00%
Minimum	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected term of option	'5 years	'5 years
Expected volatility	92.00%	87.00%
Risk free interest rate	1.88%	1.01%
Maximum	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Expected term of option	'6 years 1 month 6 days	'6 years 1 month 6 days
Expected volatility	96.00%	88.00%
Risk free interest rate	2.02%	1.69%

Changes_in_Stockholders_Equity

Changes in Stockholders' Equity (Detail) (USD $)	3 Months Ended		6 Months Ended		190 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014
Stockholders Equity [Line Items]	'	'	'	'	'
Balance at December 31, 2013 and 2012	'	'	$152,958	$72,047	'
Net loss	-15,657	-19,940	-31,745	-31,678	-399,557
Stock-based compensation	'	'	3,197	3,087	'
Exercise of stock options	'	'	1,450	298	'
Change in unrealized loss on marketable securities	'	'	19	-160	'
Issuance of common stock	'	'	'	133,211	'
Issuance of common stock under the Employee Stock Purchase Plan	'	'	96	105	'
Balance at June 30, 2014 and 2013	$125,975	$176,910	$125,975	$176,910	$125,975