Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts receivable	$ 15	$ 120
Preferred stock, par value ($ per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value ($ per share)	$ 0.001	$ 0.001
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	68,942,042	68,228,935
Common stock, shares outstanding	68,942,042	68,228,935
Series B junior participating preferred stock [Member]
Preferred stock, par value ($ per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	1,500,000	1,500,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Series E Convertible Voting Preferred Stock [Member]
Preferred stock, par value ($ per share)	$ 0.001	$ 0.001
Preferred stock, stated value ($ per share)	$ 10,000	$ 10,000
Preferred stock, shares authorized	2,000	2,000
Preferred stock, shares issued	20	20
Preferred stock, shares outstanding	20	20
Convertible preferred shares	40,000	40,000
Preferred stock, liquidation value	$ 240	$ 240