Nature of Business and Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2012
Nature of Business and Basis of Presentation [Abstract]
Basis of Presentation	*Basis of Presentation* The information reported within the Company’s financial statements from April 20, 2009 to December 31, 2010 was based solely on the accounts of Clovis Oncology, Inc. Effective January 1, 2011, Clovis Oncology UK Limited, a wholly owned subsidiary of the Company, commenced operations. All financial information presented after December 31, 2010 was consolidated and includes the accounts of the Company and its wholly owned subsidiary. 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 information prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission, or 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, 2011 for a broader discussion of our business and the opportunities and risks inherent in such business.
Use of Estimates	*Use of Estimates* The preparation of these unaudited consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, other comprehensive loss and related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to 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 public and private equity financings, and management expects operating losses and negative cash flows to continue for at least the next few years. 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. Based on the Company’s operating plan, existing working capital at June 30, 2012 is sufficient to meet the cash requirements to fund planned operations through at least the next twelve months without additional sources of cash, although there can be no assurance that this can, in fact, be accomplished.
Recently Adopted Accounting Updates	*Recently Adopted Accounting Updates* On January 1, 2012, the Company adopted Accounting Standards Update (ASU) No. 2011-05, Presentation of Comprehensive Income. The standard eliminates the option to report other comprehensive income and its components in the statement of changes in equity. An entity may present items of net income and other comprehensive income in one continuous statement, or in two separate, but consecutive statements. The Company adopted this standard on January 1, 2012.

Disclosure of accounting policy for reporting when there is a substantial doubt about an entity's ability to continue as a going concern for a reasonable period of time (generally a year from the balance sheet date). Disclose: (a) pertinent conditions and events giving rise to the assessment of substantial doubt about the entity's ability to continue as a going concern for a reasonable period of time, (b) the possible effects of such conditions and events, (c) management's evaluation of the significance of those conditions and events and any mitigating factors, (d) possible discontinuance of operations, (e) management's plans (including relevant prospective financial information), and (f) information about the recoverability or classification of recorded asset amounts or the amounts or classification of liabilities. If management's plans alleviate the substantial doubt about the entity's ability to continue as a going concern, disclosure of the principal conditions and events that initially raised the substantial doubt about the entity's ability to continue as a going concern would be expected to be considered. Disclose whether operations for the current or prior years generated sufficient cash to cover current obligations, whether waivers were obtained from creditors relating to the company's default under the provisions of debt agreements and possible effects of such conditions and events, such as: whether there is a possible need to obtain additional financing (debt or equity) or to liquidate certain holdings to offset future cash flow deficiencies. Disclose appropriate parent company information when parent is dependent upon remittances from subsidiaries to satisfy its obligations.

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Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.

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