Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Summary of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance is as follows (in thousands):

	December 31,
	2013	2012
Stock options and restricted stock units outstanding	14,859	9,901
Warrants to purchase common stock	16,189	16,292
Shares authorized for future issuance under equity and purchase plans	2,595	1,166
	33,643	27,359