Common Stock (Tables)

12 Months Ended

Dec. 31, 2013

Equity [Abstract]

Schedule of Shares Reserved for Future Issuance

The shares reserved for future issuance as of December 31, 2013 and 2012 consisted of the following:

(in thousands)	December 31, 2013		December 31, 2012
Common stock warrants		2,777		2,842
Options to purchase common stock		20,107		18,066
Conversion of the Notes		25,000		—