CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Accumulated Deficit	Accumulated Other Comprehensive Income/(Loss)	Total
Balances, beginning of period at Dec. 31, 2016	$ 455,443	$ (414,933)	$ 15	$ 40,525
Balances, beginning of period (in shares) at Dec. 31, 2016	97,786,608
Shares issued (RSUs vested, net of shares withheld)	$ (264)			(264)
Shares issued (RSUs vested, net of shares withheld) (in shares)	1,625,399
Stock-based compensation	$ 874			874
Other comprehensive loss			(17)	(17)
Net loss		(12,035)		(12,035)
Balances, end of period at Dec. 31, 2017	$ 456,053	(426,968)	(2)	29,083
Balances, end of period (in shares) at Dec. 31, 2017	99,412,007
Cumulative adjustment related to Accounting Standard Update 2016-01 | Accounting Standards Update 2016-01		(2)	$ 2
Cumulative adjustment balance	$ 456,053	(426,970)		29,083
Shares issued (RSUs vested, net of shares withheld)	$ (122)			(122)
Shares issued (RSUs vested, net of shares withheld) (in shares)	637,554
Shares issued (exercise of stock options)	$ 86			$ 86
Shares issued (exercise of stock options) (in shares)	218,600			218,600
Stock-based compensation	$ 982			$ 982
Option amendment (Note 6)	(61)			(61)
Net loss		(8,714)		(8,714)
Balances, end of period at Dec. 31, 2018	$ 456,938	$ (435,684)		$ 21,254
Balances, end of period (in shares) at Dec. 31, 2018	100,268,161