Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 4,700,000	$ 4,500,000
Proceeds from sale/maturity of short-term investments	197,466,000	89,688,000	42,063,000
Research and development	$ 104,712,000us-gaap_ResearchAndDevelopmentExpense	$ 110,008,000us-gaap_ResearchAndDevelopmentExpense	$ 112,938,000us-gaap_ResearchAndDevelopmentExpense
Common stock warrants issued, per warrant	$ 26.68
Common stock warrant
Summary Of Significant Accounting Policies [Line Items]
Common stock warrants issued, per warrant	$ 26.68
Maximum
Summary Of Significant Accounting Policies [Line Items]
Short-term investment contractual maturities	2 years	2 years

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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