Stockholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Apr. 04, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]
Common stock shares issued during period, in connection with credit facility (shares)	10,315,151
Common stock issued, price per share (usd per share)	$ 6.00			$ 5.27
Net proceeds from IPO	$ 53,800,000	$ 0	$ 58,609,000	$ 0
Underwriter's discounts and commissions	3,300,000
Other estimated offering costs	4,800,000
Convertible preferred stock, shares outstanding	22,220,856	0	0
Convertible preferred stock outstanding, value	93,600,000
Convertible notes, outstanding balance of principal and accrued paid in kind interest	21,200,000
Conversion of convertible preferred stock into common stock (shares)	25,171,017
Conversion of notes into common stock (shares)	3,533,988
Common stock conversion price per share (usd per share)	$ 6.00
Debt interest expense			$ 2,800,000
Common Stock
Class of Stock [Line Items]
Number of securities called by warrants		293,474
Common Stock | Minimum
Class of Stock [Line Items]
Warrant to purchase common stock, price per share (usd per share)		5.27
Common Stock | Maximum
Class of Stock [Line Items]
Warrant to purchase common stock, price per share (usd per share)		6.17