Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2012

Equity [Abstract]

Summary of Common Stock Reserved for Future Issuance

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

	December 31,
	2012	2011
Stock options	9,901	3,517
Warrants to purchase common stock	16,292	508
Shares authorized for future issuance under equity and purchase plans	1,166	1,681
	27,359	5,706