Clovis Oncology (CLVSQ) 10-Q8 May 152015 Q1 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2015	1-May-15
Document And Entity Information [Abstract]
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	CLVS
Entity Registrant Name	CLOVIS ONCOLOGY, INC.
Entity Central Index Key	1466301
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		34,064,765

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
License and milestone revenue		$13,625
Operating expenses:
Research and development	56,750	24,151
General and administrative	6,751	5,320
Acquired in-process research and development		8,406
Amortization of intangible asset		3,409
Accretion of contingent purchase consideration	724	822
Total expenses	64,225	42,108
Operating loss	-64,225	-28,483
Other income (expense):
Interest expense	-2,075
Foreign currency gains (losses)	3,247	-60
Other income (expense)	11	-46
Other income (expense), net	1,183	-106
Loss before income taxes	-63,042	-28,589
Income tax expense	-102	-2,129
Net loss	-63,144	-30,718
Basic and diluted net loss per common share	($1.86)	($0.91)
Basic and diluted weighted average common shares outstanding	34,011	33,820
Comprehensive loss	($88,971)	($30,199)

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$291,542	$482,677
Available-for-sale securities	141,833
Prepaid research and development expenses	3,072	3,765
Other current assets	5,257	4,730
Total current assets	441,704	491,172
Property and equipment, net	3,316	2,718
Intangible assets	187,916	212,900
Goodwill	58,303	66,055
Other assets	13,470	13,361
Total assets	704,709	786,206
Current liabilities:
Accounts payable	7,373	2,917
Accrued research and development expenses	44,547	37,257
Other accrued expenses	3,764	7,598
Total current liabilities	55,684	47,772
Contingent purchase consideration	49,659	52,453
Deferred income taxes, net	59,006	66,851
Convertible senior notes	287,500	287,500
Deferred rent, long-term	271
Total liabilities	452,120	454,576
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, par value $0.001 per share; 10,000,000 shares authorized, no shares issued and outstanding at March 31, 2015 and December 31, 2014
Common stock, $0.001 par value per share, 100,000,000 shares authorized at March 31, 2015 and December 31, 2014; 34,062,571 and 33,977,187 shares issued and outstanding at March 31, 2015 and December 31, 2014, respectively	34	34
Additional paid-in capital	795,019	785,089
Accumulated other comprehensive loss	-50,275	-24,448
Accumulated deficit	-492,189	-429,045
Total stockholders' equity	252,589	331,630
Total liabilities and stockholders' equity	$704,709	$786,206

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	34,062,571	33,977,187
Common stock, shares outstanding	34,062,571	33,977,187

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net loss	($63,144)	($30,718)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	467	3,477
Share-based compensation expense	8,682	4,936
Amortization of premiums and discounts on available-for-sale securities	471
Change in value of contingent purchase consideration	-2,794	876
Deferred income taxes		761
Changes in operating assets and liabilities:
Prepaid and accrued research and development expenses	7,776	5,731
Other operating assets	-805	-463
Accounts payable	4,228	-2,224
Other accrued expenses	-3,286	-1,910
Net cash used in operating activities	-48,405	-19,534
Investing activities
Purchases of property and equipment	-816	-220
Purchases of available-for-sale securities	-142,216
Net cash used in investing activities	-143,032	-220
Financing activities
Proceeds from the exercise of stock options and employee stock purchases	1,193	57
Net cash provided by financing activities	1,193	57
Effect of exchange rate changes on cash and cash equivalents	-891	123
Decrease in cash and cash equivalents	-191,135	-19,574
Cash and cash equivalents at beginning of period	482,677	323,228
Cash and cash equivalents at end of period	291,542	303,654
Supplemental disclosure of cash flow information:
Cash paid for interest	$3,714

Nature_of_Business_and_Basis_o

Nature of Business and Basis of Presentation	3 Months Ended
Nature of Business and Basis of Presentation	Mar. 31, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation
	Clovis Oncology, Inc. (the “Company”) is a biopharmaceutical company focused on acquiring, developing and commercializing innovative anti-cancer agents in the United States, Europe and other international markets. The Company has and intends to continue to license or acquire rights to oncology compounds in all stages of development. In exchange for the right to develop and commercialize these compounds, the Company generally expects to provide the licensor with a combination of up-front payments, milestone payments and royalties on future sales. In addition, the Company generally expects to assume the responsibility for future drug development and commercialization costs. The Company currently operates in one segment. Since inception, the Company’s operations have consisted primarily of developing in-licensed compounds, evaluating new product acquisition candidates and general corporate activities.
	Basis of Presentation
	All financial information presented includes the accounts of the Company and its wholly-owned subsidiaries, Clovis Oncology UK Limited and Clovis Oncology Italy S.r.l. All significant intercompany balances and transactions have been eliminated in consolidation.
	The unaudited financial statements of Clovis Oncology, Inc. included herein reflect all adjustments, consisting only of normal recurring adjustments, which in the opinion of management are necessary to fairly state our financial position, results of operations and cash flows for the periods presented. Interim results may not be indicative of the results that may be expected for the full year. Certain information and footnote disclosures normally included in audited financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) have been condensed or omitted pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto which are included in our Annual Report on Form 10-K for the year ended December 31, 2014 for a broader discussion of our business and the opportunities and risks inherent in such business.
	Use of Estimates
	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, revenue and related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to contingent purchase consideration, the allocation of purchase consideration, intangible asset impairment, clinical trial accruals and share-based compensation expense. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.
	Liquidity
	The Company has incurred significant net losses since inception and has relied on its ability to fund its operations through debt and equity financings. Management expects operating losses and negative cash flows to continue for the foreseeable future. As the Company continues to incur losses, transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless or until it does, the Company will continue to need to raise additional cash.
	Management intends to fund future operations through additional private or public debt or equity offerings and may seek additional capital through arrangements with strategic partners or from other sources.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies
	The Company’s significant accounting policies are described in Note 2 of the Notes to the Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
	Recent Accounting Pronouncements
	In April 2015, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2015-03, “Interest – Imputation of Interest (Subtopic 835-30) – Simplifying the Presentation of Debt Issuance Costs.” ASU No. 2015-03 requires debt issuance costs to be presented as a deduction from the corresponding debt liability, rather than as an asset. This update is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. Early adoption is permitted. Upon adoption, the guidance must be applied retrospectively to all periods presented in the financial statements. The Company has elected not to early adopt this standard. Adoption of the standard will impact the presentation of the Company’s debt issuance costs on the Consolidated Balance Sheets and the related disclosures.

EOS_Acquisition

EOS Acquisition	3 Months Ended
EOS Acquisition	Mar. 31, 2015
Business Combinations [Abstract]
EOS Acquisition	3. EOS Acquisition
	On November 19, 2013, the Company acquired all of the outstanding common and preferred stock of Ethical Oncology Science, S.p.A. (“EOS”) (now known as Clovis Oncology Italy S.r.l.). The initial purchase consideration was comprised of an $11.8 million cash payment and the issuance of $173.7 million of the Company’s common stock to the former EOS shareholders. The Company may make additional purchase payments to the previous EOS shareholders if certain lucitanib regulatory and sales milestones are achieved. The range of the potential contingent milestone payments are zero to an estimated maximum of $65.0 million and €115.0 million. The Company recorded a liability for the estimated fair value of these payments, which totaled $49.7 million and $52.5 million at March 31, 2015 and December 31, 2014, respectively.

Financial_Instruments_and_Fair

Financial Instruments and Fair Value Measurements	3 Months Ended
Financial Instruments and Fair Value Measurements	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	4. Financial Instruments and Fair Value Measurements
	Cash, Cash Equivalents and Available-for-Sale Securities
	The Company considers all highly liquid investments with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include bank demand deposits and money market funds that invest primarily in certificate of deposits, commercial paper and U.S. government and U.S. government agency obligations.
	Marketable securities with original maturities greater than three months are considered to be available-for-sale securities. Available-for-sale securities are reported at fair value and unrealized gains and losses are included in accumulated other comprehensive loss on the Consolidated Balance Sheets. Realized gains and losses, amortization of premiums and discounts and interest and dividends earned are included in other income (expense) on the Consolidated Statements of Operations and Comprehensive Loss. The cost of investments for purposes of computing realized and unrealized gains and losses is based on the specific identification method. Investments with maturities beyond one year are classified as short-term based on management’s intent to fund current operations with these securities or to make them available for current operations. A decline in the market value of a security below its cost value that is deemed to be other than temporary is charged to earnings and results in the establishment of a new cost basis for the security.
	Fair Value Measurements
	Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability (at 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. The three levels of inputs that may be used to measure fair value include:
	Level 1:	Quoted prices in active markets for identical assets or liabilities. The Company’s Level 1 assets consist of money market investments. The Company does not have Level 1 liabilities.

	Level 2:	Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities in active markets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company’s Level 2 assets include U.S. treasury securities. The Company does not have Level 2 liabilities.

	Level 3:	Unobservable inputs that are supported by little or no market activity. The Company does not have Level 3 assets. The contingent purchase consideration related to the undeveloped lucitanib product rights acquired in 2013 with the purchase of EOS is a Level 3 liability. The fair value of this liability is based on unobservable inputs and includes valuations for which there is little, if any, market activity. See Note 3 of the Company’s 2014 Form 10-K for further discussion of the unobservable inputs and valuation techniques related to the contingent purchase consideration liability.
	The following table identifies the Company’s assets and liabilities that were measured at fair value on a recurring basis (in thousands):

		Balance			Level 1		Level 2		Level 3
	March 31, 2015
	Assets:
	Money market	$	226,001		$	226,001	$	—	$	—
	U.S. treasury securities		141,833			—		141,833		—
	Total assets at fair value	$	367,834		$	226,001	$	141,833	$	—
	Liabilities:
	Contingent purchase consideration	$	49,659		$	—	$	—	$	49,659
	Total liabilities at fair value	$	49,659		$	—	$	—	$	49,659
	December 31, 2014
	Assets:
	Money market	$	447,994		$	447,994	$	—	$	—
	Total assets at fair value	$	447,994		$	447,994	$	—	$	—
	Liabilities:
	Contingent purchase consideration	$	52,453		$	—	$	—	$	52,453
	Total liabilities at fair value	$	52,453		$	—	$	—	$	52,453

	The following table rolls forward the fair value of Level 3 instruments (significant unobservable inputs) in thousands:

		For the Three
		Months Ended
		March 31, 2015
	Liabilities:
	Balance at beginning of period	$	52,453
	Accretion		724
	Change in foreign currency gains and losses		(3,518	)
	Balance at end of period	$	49,659

	The change in the fair value of Level 3 instruments is included in accretion of contingent purchase consideration and foreign currency gains (losses) for changes in the foreign currency translation rate on the Consolidated Statements of Operations and Comprehensive Loss.
	Financial instruments not recorded at fair value include the Company’s convertible senior notes. At March 31, 2015, the carrying amount of the convertible senior notes was $287.5 million, which represents the aggregate principal amount, and the fair value was $398.9 million. The fair value was determined using Level 2 inputs based on the indicative pricing published by certain investment banks or trading levels of the Notes, which are not listed on any securities exchange or quoted on an inter-dealer automated quotation system. See Note 9 for discussion of the convertible senior notes.

AvailableforSale_Securities

Available-for-Sale Securities

3 Months Ended

Mar. 31, 2015

Available For Sale Securities [Abstract]

Available-for-Sale Securities

5. Available-for-Sale Securities

As of March 31, 2015, available-for-sale securities consisted of the following (in thousands):

Gross

Aggregate

Amortized

Unrealized

Fair

Cost

Gains

Losses

Value

U.S. treasury securities

141,745

—

141,833

As of March 31, 2015, the cost or amortized cost and fair value of available-for-sale securities by contractual maturity were (in thousands):

Amortized

Fair

Cost

Value

Due in one year or less

141,745

141,833

Total

141,745

141,833

Other_Current_Assets

Other Current Assets	3 Months Ended
Other Current Assets	Mar. 31, 2015
Other Current Assets [Abstract]
Other Current Assets	6. Other Current Assets
	Other current assets were comprised of the following (in thousands):

		March 31,		December 31,
		2015		2014
	Receivable from partners	$	2,636	$	1,991
	Prepaid expenses- other		1,242		1,168
	Prepaid insurance		797		1,190
	VAT recoverable		191		231
	Other		391		150
	Total	$	5,257	$	4,730

Intangible_Assets_and_Goodwill

Intangible Assets and Goodwill	3 Months Ended
Intangible Assets and Goodwill	Mar. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	7. Intangible Assets and Goodwill
	Intangible acquired in-process research and development (“IPR&D”) assets and goodwill were established as part of the purchase accounting of EOS in November 2013.
	IPR&D assets and goodwill consisted of the following (in thousands):

			March 31,			December 31,
			2015			2014
	IPR&D assets:
	Balance at beginning of period		$	212,900		$	244,518
	Change in foreign currency gains and losses			(24,984	)		(28,209	)
	Amortization of intangible asset			—			(3,409	)	a
	Balance at end of period		$	187,916		$	212,900

	Goodwill:
	Balance at beginning of period		$	66,055		$	74,811
	Change in foreign currency gains and losses			(7,752	)		(8,756	)
	Balance at end of period		$	58,303		$	66,055
	a.	During the first quarter of 2014, the Company recorded a $3.4 million reduction in the intangible assets driven by lower expected future milestone revenue from the lucitanib development activities due to the receipt of a lucitanib milestone payment from Servier (see Note 12). This reduction was reported as amortization of intangible asset on the Consolidated Statements of Operations and Comprehensive Loss.
	Recurring amortization of the IPR&D assets will commence when the useful lives of the intangible assets have been determined. IPR&D intangible assets are evaluated for impairment at least annually or more frequently if impairment indicators exist and any reduction in fair value will be recognized as an expense in the Consolidated Statements of Operations and Comprehensive Loss.

Other_Accrued_Expenses

Other Accrued Expenses	3 Months Ended
Other Accrued Expenses	Mar. 31, 2015
Payables And Accruals [Abstract]
Other Accrued Expenses	8. Other Accrued Expenses
	Other accrued expenses were comprised of the following (in thousands):

		March 31,		December 31,
		2015		2014
	Accrued personnel costs	$	2,563	$	4,726
	Income tax payable		491		411
	Accrued interest payable		299		2,236
	Accrued expenses - other		231		148
	Accrued corporate legal fees and professional services		180		77
	Total	$	3,764	$	7,598

Convertible_Senior_Notes

Convertible Senior Notes	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Convertible Senior Notes	9. Convertible Senior Notes
	On September 9, 2014, we completed a private placement of $287.5 million aggregate principal amount of 2.5% convertible senior notes due 2021 (the “Notes”) resulting in net proceeds to the Company of $278.3 million after deducting offering expenses. In accordance with the accounting guidance, the conversion feature did not meet the criteria for bifurcation, and the entire principal amount was recorded as a long-term liability on the Consolidated Balance Sheets.

	The Notes are governed by the terms of the indenture between the Company, as issuer, and The Bank of New York Mellon Trust Company, N.A., as trustee. The Notes are senior unsecured obligations and bear interest at a rate of 2.5% per year, payable semi-annually in arrears on March 15 and September 15 of each year, beginning March 15, 2015. The Notes will mature on September 15, 2021, unless earlier converted, redeemed or repurchased.

	Holders may convert all or any portion of the Notes at any time prior to the close of business on the business day immediately preceding the maturity date. Upon conversion, the holders will receive shares of our common stock at an initial conversion rate of 16.1616 shares per $1,000 in principal amount of Notes, equivalent to a conversion price of approximately $61.88 per share. The conversion rate is subject to adjustment upon the occurrence of certain events described in the indenture, but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date or upon our issuance of a notice of redemption, we will increase the conversion rate for holders who elect to convert the Notes in connection with such a corporate event or during the related redemption period in certain circumstances.

	On or after September 15, 2018, we may redeem the Notes, at our option, in whole or in part, if the last reported sale price of our common stock has been at least 150% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending not more than two trading days preceding the date on which we provide written notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the Notes.

	If we undergo a fundamental change, as defined in the indenture, prior to the maturity date of the Notes, holders may require us to repurchase for cash all or any portion of the Notes at a fundamental change repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.
	The Notes rank senior in right of payment to any of our indebtedness that is expressly subordinated in right of payment to the Notes; equal in right of payment to all of our liabilities that are not so subordinated; effectively junior in right of payment to any secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of our subsidiaries.
	In connection with the issuance of the Notes, the Company incurred $9.2 million of debt issuance costs, which is included in other assets on the Consolidated Balance Sheets. The debt issuance costs are amortized as interest expense over the expected life of the Notes using the effective interest method. The Company determined the expected life of the debt was equal to the seven-year term of the Notes. As of March 31, 2015, the balance of unamortized debt issuance costs was $8.5 million.

	The following table sets forth total interest expense recognized related to the Notes during the three months ended March 31, 2015 (in thousands):
		For the Three
		Months Ended
		March 31, 2015
	Contractual interest expense	$	1,777
	Amortization of debt issuance costs		298
	Total interest expense	$	2,075

Stockholders_Equity

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity
	Accumulated Other Comprehensive Loss
	Accumulated other comprehensive loss consists of changes in foreign currency translation adjustments, which includes changes in a subsidiary’s functional currency, and unrealized gains and losses on available-for-sale securities.
	The accumulated balances related to each component of other comprehensive income (loss) are summarized as follows (in thousands):
							Total
		Foreign					Accumulated
		Currency					Other
		Translation			Unrealized		Comprehensive
		Adjustments			Gains		Income (Loss)
	Balance December 31, 2013	$	4,696		$	—	$	4,696
	Period change		(29,144	)		—		(29,144	)
	Balance December 31, 2014		(24,448	)		—		(24,448	)
	Period change		(25,915	)		88		(25,827	)
	Balance March 31, 2015	$	(50,363	)	$	88	$	(50,275	)

	The period change between March 31, 2015 and December 31, 2014 was primarily due to the currency translation of the IPR&D intangible assets, goodwill and deferred income taxes associated with the acquisition of EOS in November 2013 (see Notes 3 and 7).

ShareBased_Compensation

Share-Based Compensation	3 Months Ended
Share-Based Compensation	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	11. Share-Based Compensation
	Share-based compensation expense for all equity based programs, including stock options and the employee stock purchase plan, for the three months ended March 31, 2015 and 2014, respectively, was recognized in the accompanying Consolidated Statements of Operations and Comprehensive Loss as follows:

			Three Months Ended March 31,
			2015				2014
	Research and development		$	5,404			$	2,434
	General and administrative			3,278				2,502
	Total share-based compensation expense		$	8,682			$	4,936

	The Company did not recognize a tax benefit related to share-based compensation expense during the three months ended March 31, 2015 and 2014, respectively, as the Company maintains net operating loss carryforwards and has established a valuation allowance against the entire net deferred tax asset as of March 31, 2015.
	The following table summarizes the activity relating to the Company’s options to purchase common stock:

			Number of Options				Weighted		Weighted		Aggregate
							Average		Average		Intrinsic
							Exercise		Remaining		Value (Thousands)
							Price		Contractual
									Term (Years)
	Outstanding at December 31, 2014			4,159,362			$	37.69
	Granted			697,693		a		77.24
	Exercised			(85,384	)			13.98
	Forfeited			(13,535	)			45.51
	Outstanding at March 31, 2015			4,758,136			$	43.89		8.2	$	147,788
	Vested and expected to vest at March 31, 2015			4,329,211			$	41.66		8.1	$	143,406
	Exercisable at March 31, 2015			1,971,091			$	27.47		7.2	$	92,342

	(a)	Includes 120,000 performance-based stock options granted to executives of the Company. Fifty-percent of the grant vests contingent on approval by the U.S. Food and Drug Administration (“FDA”) to commercially distribute, sell or market rociletinib and fifty-percent of the grant vests contingent on approval by the FDA to commercially distribute, sell or market rucaparib. Stock compensation expense will be recognized when the condition for vesting is probable of being met.

	The aggregate intrinsic value in the table above represents the pretax intrinsic value, based on our closing stock price of $74.23 as of March 31, 2015, which would have been received by the option holders had all option holders with in-the-money options exercised their options as of that date.
	The following table summarizes information about our stock options as of and for the three months ended March 31, 2015 and 2014:
			Three Months Ended March 31,
			2015				2014
	Weighted-average grant date fair value per share		$	49.75			$	46.38
	Intrinsic value of options exercised		$	5,087			$	285,808
	Cash received from stock option exercises		$	1,193			$	56,651

	As of March 31, 2015, the unrecognized share-based compensation expense related to nonvested options, adjusted for expected forfeitures, was $70.7 million and the estimated weighted-average remaining vesting period was 3.2 years.

License_Agreements

License Agreements	3 Months Ended
License Agreements	Mar. 31, 2015
Research And Development [Abstract]
License Agreements	12. License Agreements
	Rociletinib (CO-1686)
	In May 2010, we entered into an exclusive worldwide license agreement with Avila Therapeutics, Inc. (now Celgene Avilomics Research, Inc., part of Celgene Corporation (“Celgene”)) to discover, develop and commercialize a covalent inhibitor of mutant forms of the epidermal growth factor receptor (“EGFR”) gene product. As a result of the collaboration contemplated by the agreement, rociletinib was identified as the lead inhibitor candidate, which we are developing under the terms of the license agreement. We are responsible for all preclinical, clinical, regulatory and other activities necessary to develop and commercialize rociletinib. We made an up-front payment of $2.0 million upon execution of the license agreement, a $4.0 million milestone payment in the first quarter of 2012 upon acceptance by the U.S. Food and Drug Administration of our Investigational New Drug application for rociletinib and a $5.0 million milestone payment in the first quarter of 2014 upon initiation of the Phase II study for rociletinib. We recognized all payments as acquired in-process research and development expense.
	We are obligated to pay royalties on net sales of rociletinib, based on the volume of annual net sales achieved. The Company is required to pay up to an additional aggregate of $110.0 million in development and regulatory milestone payments if certain clinical study objectives and regulatory filings, acceptances and approvals are achieved. In addition, the Company is required to pay up to an aggregate of $120.0 million in sales milestone payments if certain annual sales targets are achieved.
	Rucaparib
	In June 2011, the Company entered into a worldwide license agreement with Pfizer Inc. to acquire exclusive development and commercialization rights to rucaparib. This drug candidate is a small molecule inhibitor of poly (ADP-ribose) polymerase (“PARP”), which the Company is developing for the treatment of selected solid tumors. Pursuant to the terms of the license agreement, the Company made a $7.0 million up-front payment to Pfizer. In April 2014, the Company initiated a pivotal registration study for rucaparib, which resulted in a $0.4 million milestone payment to Pfizer as required by the license agreement. This payment was recognized as acquired in-process research and development expense.
	The Company is responsible for all development and commercialization costs of rucaparib. When and if commercial sales of rucaparib begin, we will pay Pfizer tiered royalties on our net sales. In addition, Pfizer is eligible to receive up to $258.5 million of further payments, in aggregate, if certain development, regulatory and sales milestones are achieved.
	Lucitanib
	In connection with its November 2013 acquisition of EOS, the Company gained rights to develop and commercialize lucitanib, an oral, selective tyrosine kinase inhibitor. As further described below, EOS licensed the worldwide rights, excluding China, to develop and commercialize lucitanib from Advenchen Laboratories LLC (“Advenchen”). Subsequently, rights to develop and commercialize lucitanib in markets outside the U.S. and Japan were sublicensed by EOS to Les Laboratoires Servier (“Servier”) in exchange for up-front milestone fees, royalties on sales of lucitanib in the sublicensed territories and research and development funding commitments.
	In October 2008, EOS entered into an exclusive license agreement with Advenchen to develop and commercialize lucitanib on a global basis, excluding China. The Company is obligated to pay Advenchen royalties on net sales of lucitanib, based on the volume of annual net sales achieved. In addition, the Company is obligated to pay to Advenchen 25% of any consideration, excluding royalties, received pursuant to any sublicense agreements for lucitanib, including the agreement with Servier. In the first quarter of 2014, the Company recognized acquired in-process research and development expense of $3.4 million, which represents 25% of the sublicense agreement consideration of $13.6 million received from Servier upon the end of opposition and appeal of the lucitanib patent by the European Patent Office.
	In September 2012, EOS entered into a collaboration and license agreement with Servier whereby EOS sublicensed to Servier exclusive rights to develop and commercialize lucitanib in all countries outside of the U.S., Japan and China. In exchange for these rights, EOS received an up-front payment and is entitled to receive additional payments upon achievement of specified development, regulatory and commercial milestones up to an additional €90.0 million in the aggregate. In addition, the Company is entitled to receive sales milestone payments if specified annual sales targets for lucitanib are met, which, in the aggregate, could total €250.0 million. The Company is also entitled to receive royalties on net sales of lucitanib by Servier.
	The development, regulatory and commercial milestones represent non-refundable amounts that would be paid by Servier to the Company if certain milestones are achieved in the future. These milestones, if achieved, are substantive as they relate solely to past performance, are commensurate with estimated enhancement of value associated with the achievement of each milestone as a result of the Company's performance, which are reasonable relative to the other deliverables and terms of the arrangement, and are unrelated to the delivery of any further elements under the arrangement.
	The Company and Servier are developing lucitanib pursuant to a development plan agreed to between the parties. Servier is responsible for all of the initial global development costs under the agreed upon plan up to €80.0 million. Cumulative global development costs, if any, in excess of €80.0 million will be shared equally between the Company and Servier. Beginning in the third quarter of 2014, depending on the expense type, reimbursements are determined using a standard rate approved by the Company and Servier or actual costs incurred. Previously, reimbursements were determined based on actual costs. Reimbursements are recorded as a reduction to research and development expense in the Consolidated Statements of Operations and Comprehensive Loss.
	The Company recorded a $2.6 million and $2.0 million receivable at March 31, 2015 and December 31, 2014, respectively, for the reimbursable development costs incurred under the global development plan, which is included in other current assets on the Consolidated Balance Sheets. For the three months ending March 31, 2015 and 2014, we incurred $3.6 million and $1.8 million, respectively, in research and development costs and recorded reductions in research and development expense of $2.7 million and $1.6 million, respectively, for reimbursable development costs due from Servier.

Net_Loss_Per_Common_Share

Net Loss Per Common Share	3 Months Ended
Net Loss Per Common Share	Mar. 31, 2015
Earnings Per Share [Abstract]
Net Loss Per Common Share	13. Net Loss Per Common Share
	Basic net loss per share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common share equivalents outstanding using the treasury-stock method for the stock options and the if-converted method for the Notes. As a result of our net losses for the periods presented, all potentially dilutive common share equivalents were considered anti-dilutive and were excluded from the computation of diluted net loss per share.
	The shares outstanding at the end of the respective periods presented in the table below were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (in thousands):
		Three Months Ended March 31,
		2015		2014
	Common shares under option		4,005		2,379
	Convertible senior notes		4,646		—
	Total potential dilutive shares		8,651		2,379

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies
	Royalty and License Fee Commitments
	The Company has entered into certain license agreements, as identified in Note 12, with third parties that include the payment of development and regulatory milestones, as well as royalty payments, upon the achievement of pre-established development, regulatory and commercial targets. The Company’s payment obligation related to these license agreements is contingent upon the successful development, regulatory approval and commercialization of the licensed products. Due to the nature of these arrangements, the future potential payments are inherently uncertain, and accordingly, no amounts have been recorded in the Company’s Consolidated Balance Sheets at March 31, 2015 and December 31, 2014.
	Development and Manufacturing Agreement Commitments
	In February 2013, the Company entered into a development and manufacturing agreement with a third-party supplier for the production of the active ingredient for rucaparib. Under the Development and Manufacturing Agreement, the Company will provide the third-party supplier a rolling 24-month forecast that will be updated by the Company on a quarterly basis. The Company is obligated to order the quantity specified in the first 12 months of any forecast. As of March 31, 2015, $3.0 million of purchase commitments were established under this agreement.

Subsequent_Events

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	15. Subsequent Events
Subsequent Events	The Company evaluated events up to the filing date of these interim financial statements and determined that no subsequent activity required disclosure.

Nature_of_Business_and_Basis_o1

Nature of Business and Basis of Presentation (Policies)	3 Months Ended
Nature of Business and Basis of Presentation (Policies)	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	All financial information presented includes the accounts of the Company and its wholly-owned subsidiaries, Clovis Oncology UK Limited and Clovis Oncology Italy S.r.l. All significant intercompany balances and transactions have been eliminated in consolidation.
	The unaudited financial statements of Clovis Oncology, Inc. included herein reflect all adjustments, consisting only of normal recurring adjustments, which in the opinion of management are necessary to fairly state our financial position, results of operations and cash flows for the periods presented. Interim results may not be indicative of the results that may be expected for the full year. Certain information and footnote disclosures normally included in audited financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) have been condensed or omitted pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto which are included in our Annual Report on Form 10-K for the year ended December 31, 2014 for a broader discussion of our business and the opportunities and risks inherent in such business.
Use of Estimates	Use of Estimates
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, revenue and related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to contingent purchase consideration, the allocation of purchase consideration, intangible asset impairment, clinical trial accruals and share-based compensation expense. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.
Liquidity	Liquidity
	The Company has incurred significant net losses since inception and has relied on its ability to fund its operations through debt and equity financings. Management expects operating losses and negative cash flows to continue for the foreseeable future. As the Company continues to incur losses, transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support the Company’s cost structure. The Company may never achieve profitability, and unless or until it does, the Company will continue to need to raise additional cash.
	Management intends to fund future operations through additional private or public debt or equity offerings and may seek additional capital through arrangements with strategic partners or from other sources.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
Recent Accounting Pronouncements	In April 2015, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) No. 2015-03, “Interest – Imputation of Interest (Subtopic 835-30) – Simplifying the Presentation of Debt Issuance Costs.” ASU No. 2015-03 requires debt issuance costs to be presented as a deduction from the corresponding debt liability, rather than as an asset. This update is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. Early adoption is permitted. Upon adoption, the guidance must be applied retrospectively to all periods presented in the financial statements. The Company has elected not to early adopt this standard. Adoption of the standard will impact the presentation of the Company’s debt issuance costs on the Consolidated Balance Sheets and the related disclosures.

Financial_Instruments_and_Fair1

Financial Instruments and Fair Value Measurements (Tables)	3 Months Ended
Financial Instruments and Fair Value Measurements (Tables)	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table identifies the Company’s assets and liabilities that were measured at fair value on a recurring basis (in thousands):

		Balance			Level 1		Level 2		Level 3
	March 31, 2015
	Assets:
	Money market	$	226,001		$	226,001	$	—	$	—
	U.S. treasury securities		141,833			—		141,833		—
	Total assets at fair value	$	367,834		$	226,001	$	141,833	$	—
	Liabilities:
	Contingent purchase consideration	$	49,659		$	—	$	—	$	49,659
	Total liabilities at fair value	$	49,659		$	—	$	—	$	49,659
	December 31, 2014
	Assets:
	Money market	$	447,994		$	447,994	$	—	$	—
	Total assets at fair value	$	447,994		$	447,994	$	—	$	—
	Liabilities:
	Contingent purchase consideration	$	52,453		$	—	$	—	$	52,453
	Total liabilities at fair value	$	52,453		$	—	$	—	$	52,453

Roll-forward of Fair Value of Level 3 Instruments (significant unobservable inputs)	The following table rolls forward the fair value of Level 3 instruments (significant unobservable inputs) in thousands:

		For the Three
		Months Ended
		March 31, 2015
	Liabilities:
	Balance at beginning of period	$	52,453
	Accretion		724
	Change in foreign currency gains and losses		(3,518	)
	Balance at end of period	$	49,659

AvailableforSale_Securities_Ta

Available-for-Sale Securities (Tables)

3 Months Ended

Mar. 31, 2015

Available For Sale Securities [Abstract]

Summary of Available-for-Sale Securities

As of March 31, 2015, available-for-sale securities consisted of the following (in thousands):

Gross

Aggregate

Amortized

Unrealized

Fair

Cost

Gains

Losses

Value

U.S. treasury securities

141,745

—

141,833

Summary of Cost or Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity

As of March 31, 2015, the cost or amortized cost and fair value of available-for-sale securities by contractual maturity were (in thousands):

Amortized

Fair

Cost

Value

Due in one year or less

141,745

141,833

Total

141,745

141,833

Other_Current_Assets_Tables

Other Current Assets (Tables)	3 Months Ended
Other Current Assets (Tables)	Mar. 31, 2015
Other Current Assets [Abstract]
Other Current Assets	Other current assets were comprised of the following (in thousands):

		March 31,		December 31,
		2015		2014
	Receivable from partners	$	2,636	$	1,991
	Prepaid expenses- other		1,242		1,168
	Prepaid insurance		797		1,190
	VAT recoverable		191		231
	Other		391		150
	Total	$	5,257	$	4,730

Intangible_Assets_and_Goodwill1

Intangible Assets and Goodwill (Tables)	3 Months Ended
Intangible Assets and Goodwill (Tables)	Mar. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of IPR&D Assets and Goodwill	IPR&D assets and goodwill consisted of the following (in thousands):

			March 31,			December 31,
			2015			2014
	IPR&D assets:
	Balance at beginning of period		$	212,900		$	244,518
	Change in foreign currency gains and losses			(24,984	)		(28,209	)
	Amortization of intangible asset			—			(3,409	)	a
	Balance at end of period		$	187,916		$	212,900

	Goodwill:
	Balance at beginning of period		$	66,055		$	74,811
	Change in foreign currency gains and losses			(7,752	)		(8,756	)
	Balance at end of period		$	58,303		$	66,055
	a.	During the first quarter of 2014, the Company recorded a $3.4 million reduction in the intangible assets driven by lower expected future milestone revenue from the lucitanib development activities due to the receipt of a lucitanib milestone payment from Servier (see Note 12). This reduction was reported as amortization of intangible asset on the Consolidated Statements of Operations and Comprehensive Loss.

Other_Accrued_Expenses_Tables

Other Accrued Expenses (Tables)	3 Months Ended
Other Accrued Expenses (Tables)	Mar. 31, 2015
Payables And Accruals [Abstract]
Other Accrued Expenses	Other accrued expenses were comprised of the following (in thousands):

		March 31,		December 31,
		2015		2014
	Accrued personnel costs	$	2,563	$	4,726
	Income tax payable		491		411
	Accrued interest payable		299		2,236
	Accrued expenses - other		231		148
	Accrued corporate legal fees and professional services		180		77
	Total	$	3,764	$	7,598

Convertible_Senior_Notes_Table

Convertible Senior Notes (Tables)	3 Months Ended
Convertible Senior Notes (Tables)	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of Total Interest Expense Recognized Related to Notes	The following table sets forth total interest expense recognized related to the Notes during the three months ended March 31, 2015 (in thousands):
		For the Three
		Months Ended
		March 31, 2015
	Contractual interest expense	$	1,777
	Amortization of debt issuance costs		298
	Total interest expense	$	2,075

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
Stockholders' Equity (Tables)	Mar. 31, 2015
Equity [Abstract]
Component of Other Comprehensive Income (Loss)	The accumulated balances related to each component of other comprehensive income (loss) are summarized as follows (in thousands):
							Total
		Foreign					Accumulated
		Currency					Other
		Translation			Unrealized		Comprehensive
		Adjustments			Gains		Income (Loss)
	Balance December 31, 2013	$	4,696		$	—	$	4,696
	Period change		(29,144	)		—		(29,144	)
	Balance December 31, 2014		(24,448	)		—		(24,448	)
	Period change		(25,915	)		88		(25,827	)
	Balance March 31, 2015	$	(50,363	)	$	88	$	(50,275	)

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	3 Months Ended
Share-Based Compensation (Tables)	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation Expense Recognized in Accompanying Statements of Operations	Share-based compensation expense for all equity based programs, including stock options and the employee stock purchase plan, for the three months ended March 31, 2015 and 2014, respectively, was recognized in the accompanying Consolidated Statements of Operations and Comprehensive Loss as follows:

			Three Months Ended March 31,
			2015				2014
	Research and development		$	5,404			$	2,434
	General and administrative			3,278				2,502
	Total share-based compensation expense		$	8,682			$	4,936

Summary of Stock Options Activity	The following table summarizes the activity relating to the Company’s options to purchase common stock:

			Number of Options				Weighted		Weighted		Aggregate
							Average		Average		Intrinsic
							Exercise		Remaining		Value (Thousands)
							Price		Contractual
									Term (Years)
	Outstanding at December 31, 2014			4,159,362			$	37.69
	Granted			697,693		a		77.24
	Exercised			(85,384	)			13.98
	Forfeited			(13,535	)			45.51
	Outstanding at March 31, 2015			4,758,136			$	43.89		8.2	$	147,788
	Vested and expected to vest at March 31, 2015			4,329,211			$	41.66		8.1	$	143,406
	Exercisable at March 31, 2015			1,971,091			$	27.47		7.2	$	92,342

	a.	Includes 120,000 performance-based stock options granted to executives of the Company. Fifty-percent of the grant vests contingent on approval by the U.S. Food and Drug Administration (“FDA”) to commercially distribute, sell or market rociletinib and fifty-percent of the grant vests contingent on approval by the FDA to commercially distribute, sell or market rucaparib. Stock compensation expense will be recognized when the condition for vesting is probable of being met.
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award	The following table summarizes information about our stock options as of and for the three months ended March 31, 2015 and 2014:
			Three Months Ended March 31,
			2015				2014
	Weighted-average grant date fair value per share		$	49.75			$	46.38
	Intrinsic value of options exercised		$	5,087			$	285,808
	Cash received from stock option exercises		$	1,193			$	56,651

Net_Loss_Per_Common_Share_Tabl

Net Loss Per Common Share (Tables)	3 Months Ended
Net Loss Per Common Share (Tables)	Mar. 31, 2015
Earnings Per Share [Abstract]
Shares Outstanding Excluded from Calculation of Diluted Net Loss Per Share	The shares outstanding at the end of the respective periods presented in the table below were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (in thousands):
		Three Months Ended March 31,
		2015		2014
	Common shares under option		4,005		2,379
	Convertible senior notes		4,646		—
	Total potential dilutive shares		8,651		2,379

EOS_Acquisition_Additional_Inf

EOS Acquisition - Additional Information (Detail) (Ethical Oncology Science, S.p.A.)	0 Months Ended					0 Months Ended
	Nov. 19, 2013	Mar. 31, 2015	Dec. 31, 2014	Nov. 19, 2013	Nov. 19, 2013	Nov. 19, 2013
	USD ($)	USD ($)	USD ($)	Regulatory and Sales Milestones	Regulatory and Sales Milestones	Common Stock
				USD ($)	EUR (€)	USD ($)
Business Acquisition [Line Items]
Business acquisition cash payments made on acquisition	$11,800,000
Business acquisition, common stock issued at acquisition date						173,700,000
Future maximum contingent milestone payments				65,000,000	115,000,000
Future minimum contingent milestone payments				0	0
Fair value of contingent consideration		$49,700,000	$52,500,000

Assets_and_Liabilities_Measure

Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	$367,834	$447,994
Contingent purchase consideration, fair value	49,659	52,453
Liabilities at fair value	49,659	52,453
Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	226,001	447,994
Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	141,833
Fair Value, Inputs, Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent purchase consideration, fair value	49,659	52,453
Liabilities at fair value	49,659	52,453
Money Market
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	226,001	447,994
Money Market \| Fair Value, Inputs, Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	226,001	447,994
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	141,833
U.S. Treasury Securities \| Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets at fair value	$141,833

Rollforward_of_Fair_Value_of_L

Roll-forward of Fair Value of Level 3 Instruments (significant unobservable inputs) (Detail) (Fair Value, Inputs, Level 3, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Fair Value, Inputs, Level 3
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$52,453
Accretion	724
Change in foreign currency gains and losses	-3,518
Balance at end of period	$49,659

Financial_Instruments_and_Fair2

Financial Instruments and Fair Value Measurements - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Sep. 09, 2014
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Convertible senior notes	$287,500,000	$287,500,000
Convertible Senior Unsecured Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Convertible senior notes	287,500,000		287,500,000
Convertible Senior Unsecured Notes \| Fair Value, Inputs, Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Convertible senior notes, fair value	$398,900,000

AvailableforSale_Securities_Su

Available-for-Sale Securities - Summary of Available-for-Sale Securities (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$141,745
Aggregate Fair Value	141,833
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	141,745
Gross Unrealized Gains	88
Gross Unrealized Losses	0
Aggregate Fair Value	$141,833

AvailableforSale_Securities_Su1

Available-for-Sale Securities - Summary of Cost or Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity (Details) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Available For Sale Securities Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$141,745
Amortized Cost	141,745
Fair Value, Due in one year or less	141,833
Aggregate Fair Value	$141,833

Other_Current_Assets_Detail

Other Current Assets (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Other Current Assets [Abstract]
Receivable from partners	$2,636	$1,991
Prepaid expenses- other	1,242	1,168
Prepaid insurance	797	1,190
VAT recoverable	191	231
Other	391	150
Other current assets	$5,257	$4,730

Summary_of_IPRD_Assets_and_Goo

Summary of IPR&D Assets and Goodwill (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014
IPR&D assets:
Amortization of intangible asset	($3,409)
Balance at end of period		187,916	212,900
Goodwill:
Balance at end of period		58,303	66,055
In Process Research and Development
IPR&D assets:
Balance at beginning of period	244,518	212,900	244,518
Change in foreign currency gains and losses		-24,984	-28,209
Amortization of intangible asset			-3,409
Balance at end of period		187,916	212,900
Ethical Oncology Science, S.p.A.
Goodwill:
Balance at beginning of period	74,811	66,055	74,811
Change in foreign currency gains and losses		-7,752	-8,756
Balance at end of period		$58,303	$66,055

Summary_of_IPRD_Assets_and_Goo1

Summary of IPR&D Assets and Goodwill (Parenthetical) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible asset	$3,409

Other_Accrued_Expenses_Detail

Other Accrued Expenses (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Accrued personnel costs	$2,563	$4,726
Income tax payable	491	411
Accrued interest payable	299	2,236
Accrued expenses - other	231	148
Accrued corporate legal fees and professional services	180	77
Other accrued expenses	$3,764	$7,598

Convertible_Senior_Notes_Addit

Convertible Senior Notes - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Sep. 09, 2014	Mar. 31, 2015	Dec. 31, 2014
	TD	TD	Dec. 31, 2014
Debt Instrument [Line Items]
Convertible senior notes, aggregate principal amount		$287,500,000	$287,500,000
Convertible Senior Unsecured Notes
Debt Instrument [Line Items]
Convertible senior notes, aggregate principal amount	287,500,000	287,500,000
Convertible senior notes, interest rate	2.50%
Net proceeds from convertible senior notes	278,300,000
Convertible senior notes, frequency of periodic payment		semi-annually
Debt instrument, beginning date of periodic payment		15-Mar-15
Convertible senior notes, maturity date		15-Sep-21
Convertible senior notes, initial conversion price per share	$61.88
Common stock initial conversion rate per $1,000 in principal amount	16.1616
Last reported sale price of common stock	150.00%
Debt instrument, conversion in effect for number of trading days	20
Debt instrument conversion, consecutive trading day period	30 days
Debt instrument redemption price percentage to principal amount	100.00%
Debt instrument redemption description		On or after September 15, 2018, we may redeem the Notes, at our option, in whole or in part, if the last reported sale price of our common stock has been at least 150% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending not more than two trading days preceding the date on which we provide written notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the Notes.
Debt instrument, redemption period start date		15-Sep-18
Debt instrument, trading days preceding redemption notice, maximum		2
Debt instrument repurchase percentage		100.00%
Debt issuance costs		9,200,000
Debt instrument term		7 years
Unamortized debt issuance costs		$8,500,000
Convertible Senior Unsecured Notes \| Semi Annual Payment, First payment date
Debt Instrument [Line Items]
Interest payment date on senior notes		-12
Convertible Senior Unsecured Notes \| Semi Annual Payment, Second payment date
Debt Instrument [Line Items]
Interest payment date on senior notes		-6

Schedule_of_Total_Interest_Exp

Schedule of Total Interest Expense Recognized Related to Notes (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Debt Disclosure [Abstract]
Contractual interest expense	$1,777
Amortization of debt issuance costs	298
Total interest expense	$2,075

Component_of_Other_Comprehensi

Component of Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	($24,448)	$4,696
Period change	-25,827	-29,144
Ending balance	-50,275	-24,448
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	-24,448	4,696
Period change	-25,915	-29,144
Ending balance	-50,363	-24,448
Unrealized Gains
Accumulated Other Comprehensive Income Loss [Line Items]
Period change	88
Ending balance	$88

ShareBased_Compensation_Expens

Share-Based Compensation Expense Recognized in Accompanying Statements of Operations (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]
Share-based compensation expense	$8,682	$4,936
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	5,404	2,434
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$3,278	$2,502

ShareBased_Compensation_Additi

Share-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation expense, tax benefit recognized	$0	$0
Pretax intrinsic value, closing stock price	$74.23
Unrecognized stock-based compensation expense related to nonvested options	$70,700,000
Unrecognized stock-based compensation expense related to nonvested options, weighted-average remaining vesting period	3 years 2 months 12 days

Summary_of_Stock_Options_Activ

Summary of Stock Options Activity (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Number of Options Outstanding	4,159,362
Number of Options, Granted	697,693
Number of Options, Exercised	-85,384
Number of Options, Forfeited	-13,535
Ending Balance, Number of Options Outstanding	4,758,136
Number of Options, Vested and expected to vest at March 31, 2015	4,329,211
Number of Options, Exercisable at March 31, 2015	1,971,091
Beginning Balance, Weighted Average Exercise Price	$37.69
Granted, Weighted Average Exercise Price	$77.24
Exercised, Weighted Average Exercise Price	$13.98
Forfeited, Weighted Average Exercise Price	$45.51
Ending Balance, Weighted Average Exercise Price	$43.89
Vested and expected to vest, Weighted Average Exercise Price	$41.66
Exercisable, Weighted Average Exercise Price	$27.47
Outstanding, Weighted Average Remaining Contractual Term (Years)	8 years 2 months 12 days
Vested and expected to vest, Weighted Average Remaining Contractual Term (Years)	8 years 1 month 6 days
Exercisable, Weighted Average Remaining Contractual Term (Years)	7 years 2 months 12 days
Outstanding, Aggregate Intrinsic Value	$147,788
Vested and expected to vest, Aggregate Intrinsic Value	143,406
Exercisable, Aggregate Intrinsic Value	$92,342

Summary_of_Stock_Options_Activ1

Summary of Stock Options Activity (Parenthetical) (Detail)	3 Months Ended
Summary of Stock Options Activity (Parenthetical) (Detail)	Mar. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options, Granted	697,693
Performance Shares \| Contingent on FDA Approval to Commercially Distribute, Sell or Market Rociletinib
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of grant vest contingent on approval	50.00%
Performance Shares \| Contingent on FDA Approval to Commercially Distribute, Sell or Market Rucaparib
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of grant vest contingent on approval	50.00%
Performance Shares \| Executive Officer
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Options, Granted	120,000

Schedule_of_ShareBased_Compens

Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Weighted-average grant date fair value per share	$49.75	$46.38
Intrinsic value of options exercised	$5,087	$285,808
Cash received from stock option exercises	$1,193	$56,651

License_Agreements_Additional_

License Agreements - Additional Information (Detail)

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

Sep. 30, 2012

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

31-May-10

Mar. 31, 2015

Apr. 30, 2014

Jun. 30, 2011

Mar. 31, 2015

Oct. 31, 2008

Mar. 31, 2014

Mar. 31, 2012

USD ($)

License Agreements Lucitanib

License Agreement Terms

Regulatory Milestone Payment

EUR (€)

USD ($)

License Agreements Licensor Celgene Avilomics Research Inc

License Agreements Licensor Pfizer

Advenchen Laboratories LLC

License Agreement Terms

Name of drug product in-licensed by the entity - Rociletinib

Rucaparib

License Agreements Lucitanib

License Agreements Licensor Celgene Avilomics Research Inc

USD ($)

Name of drug product in-licensed by the entity - Rociletinib

USD ($)

Research And Development Arrangement Contract To Perform For Others [Line Items]

Up-front payment

$2,000,000

$7,000,000

Acquired in process research and development costs

8,406,000

400,000

3,400,000

5,000,000

4,000,000

Future expected regulatory and development payment

110,000,000

Sales milestone payments

120,000,000

Future expected development, regulatory and sales milestone payments

258,500,000

Percentage of Non-Royalty Consideration Payable on Sublicense Agreements

25.00%

Sublicense agreement consideration

13,600,000

Additional payments receivable on milestone achievements

90,000,000

Additional payments receivable on attaining the sales target

250,000,000

Initial global development costs reimbursable

80,000,000

Development cost receivable

2,636,000

1,991,000

2,636,000

1,991,000

Research and development

56,750,000

24,151,000

3,600,000

1,800,000

Reduction in research and development expense for reimbursable development costs due from Servier

$2,700,000

$1,600,000

Shares_Outstanding_Excluded_fr

Shares Outstanding Excluded from Calculation of Diluted Net Loss Per Share (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]
Total potential dilutive shares	8,651	2,379
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	4,005	2,379
Convertible senior notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Total potential dilutive shares	4,646

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended
In Millions, unless otherwise specified	Feb. 28, 2013	Mar. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Purchase commitment		$3
Contractual agreement quarterly forecasts required period	24 months
Contractual agreement obligated forecast period	12 months