Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2014

Equity [Abstract]

Summary of Common Stock Reserved for Future Issuance

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

	December 31,
	2014	2013
Stock options and restricted stock units outstanding	16,913	14,859
Warrants to purchase common stock	16,232	16,189
Shares authorized for future issuance under equity and purchase plans	4,826	2,595
	37,971	33,643