CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2013	$ 76,932	$ 410	$ 456,993	$ 3,375	$ (383,846)
Beginning balance, Shares at Dec. 31, 2013		40,983
Net income (loss)	28,068				28,068
Net unrealized change on investments (net of tax (benefit) of $923, $(861) & (1,172) for year 2014, 2015 & 2016 respectively)	1,715			1,715
Forfeitures and repurchases of restricted common stock, Value	(10)		(10)
Forfeitures and repurchases of restricted common stock, Shares		(4)
Stock-based compensation, Value	185		185
Stock-based compensation, Shares		6
Issuance of shares under Employee Stock Purchase Plan, Value	74		74
Issuance of shares under Employee Stock Purchase Plan, Shares		31
Ending balance at Dec. 31, 2014	106,964	$ 410	457,242	5,090	(355,778)
Ending balance, Shares at Dec. 31, 2014		41,016
Net income (loss)	(1,930)				(1,930)
Net unrealized change on investments (net of tax (benefit) of $923, $(861) & (1,172) for year 2014, 2015 & 2016 respectively)	(1,599)			(1,599)
Stock-based compensation, Value	144		144
Stock-based compensation, Shares		7
Issuance of shares under Employee Stock Purchase Plan, Value	91	$ 1	90
Issuance of shares under Employee Stock Purchase Plan, Shares		37
Ending balance at Dec. 31, 2015	$ 103,670	$ 411	457,476	3,491	(357,708)
Ending balance, Shares at Dec. 31, 2015	41,060	41,060
Net income (loss)	$ (29,282)				(29,282)
Net unrealized change on investments (net of tax (benefit) of $923, $(861) & (1,172) for year 2014, 2015 & 2016 respectively)	(2,175)			(2,175)
Stock-based compensation, Value	207		207
Stock-based compensation, Shares		7
Vested restricted stock units, net of repurchases, Value	(10)		(10)
Vested restricted stock units, net of repurchases, Shares		29
Issuance of shares under Employee Stock Purchase Plan, Value	78	$ 1	77
Issuance of shares under Employee Stock Purchase Plan, Shares		64
Ending balance at Dec. 31, 2016	$ 72,488	$ 412	$ 457,750	$ 1,316	$ (386,990)
Ending balance, Shares at Dec. 31, 2016	41,160	41,160