Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 5,000	$ 4,700
Proceeds from sale/maturity of short-term investments	192,994	197,466	$ 89,688
Research and development	$ 101,950	$ 104,712	$ 110,008
Repurchase of common stock, shares	1.8
Common Stock Warrants
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