Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2011	$ 166,025	$ 32	$ 429,813	$ (25,000)	$ (238,812)	$ (8)
Beginning Balance, shares at Dec. 31, 2011		32,262,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan, shares		1,393,000
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan	1,599	2	1,597
Taxes withheld on net settled vesting of restricted stock units	(433)		(433)
Share-based compensation	7,500		7,500
Net loss	(89,266)				(89,266)
Other comprehensive income (loss)	22					22
Ending Balance at Dec. 31, 2012	85,447	34	438,477	(25,000)	(328,078)	14
Ending Balance, shares at Dec. 31, 2012		33,655,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan, shares		442,000
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan	102	0	102
Taxes withheld on net settled vesting of restricted stock units	(654)		(654)
Share-based compensation	3,443		3,443
Net loss	(43,413)				(43,413)
Other comprehensive income (loss)	(9)					(9)
Ending Balance at Dec. 31, 2013	44,916	34	441,368	(25,000)	(371,491)	5
Ending Balance, shares at Dec. 31, 2013		34,097,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan, shares		689,000
Exercise of stock options, vesting of restricted stock units and shares issued under employee stock purchase plan	248	2	246
Issuance of common shares in litigation settlement (in shares)		2,407,000
Issuance of common shares in connection with litigation settlement	5,000	2	4,998
Issuance of common shares in HC2 financing transaction (in shares)		7,363,000
Issuance of common shares in connection with financing transaction, net of issuance costs	7,936	7	7,929
Taxes withheld on net settled vesting of restricted stock units	(1,067)		(1,067)
Issuance of common shares for conversion of Series C Preferred Shares (in shares)		872,000
Issuance of common shares in connection with the conversion of Series C preferred shares	940	1	939
Beneficial conversion feature of convertible Series C preferred shares	445		445
Reclassification of warrant liability	8,219		8,219
Share-based compensation (in shares)		314,000
Share-based compensation	3,588		3,588
Net loss	(39,674)				(39,674)
Other comprehensive income (loss)	(5)					(5)
Ending Balance at Dec. 31, 2014	$ 30,546	$ 46	$ 466,665	$ (25,000)	$ (411,165)	$ 0
Ending Balance, shares at Dec. 31, 2014		45,742,000