Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant-date fair value of options granted (in dollars per share)	$ 3.33	$ 5.00	$ 3.12	$ 4.82
Total intrinsic value of options exercised	$ 1	$ 26	$ 1	$ 46
Total intrinsic value of options outstanding	13		13
Total intrinsic value of options exercisable	13		13
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, aggregate intrinsic value	13		13
Total unrecognized compensation	$ 4,000		$ 4,000
Weighted average periods			2 years 9 months 18 days
Assumptions used in computing the fair value [Abstract]
Risk-free interest rate	1.51%	2.29%	1.54%	1.99%
Expected life	7 years 2 months 12 days	7 years 3 months 29 days	6 years 9 months 14 days	6 years 10 months 2 days
Expected volatility	72.00%	84.00%	74.00%	81.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Options, Outstanding [Roll Forward]
Outstanding - beginning balance (in shares)			5,134,000
Granted (in shares)	1,112,000
Exercised (in shares)	(2,000)
Cancelled (in shares)	(362,000)
Expired (in shares)	(65,000)
Outstanding - ending balance (in shares)	5,817,000		5,817,000		5,134,000
Exercisable (in shares)	4,244,000		4,244,000
Vested and expected to vest (in shares)	5,503,000		5,503,000
Weighted Average Exercise Price [Roll Forward]
Outstanding - beginning balance (in dollars per share)			$ 9.05
Granted (in dollars per share)	$ 4.58
Exercised (in dollars per share)	4.70
Cancelled (in dollars per share)	6.03
Expired (in dollars per share)	27.57
Outstanding - ending balance (in dollars per share)	8.18		8.18		$ 9.05
Exercisable (in dollars per share)	9.19		9.19
Vested and expected to vest (in dollars per share)	$ 8.33		$ 8.33
Weighted Average Remaining Contractual Term [Abstract]
Options outstanding	6 years 18 days				5 years 8 months 8 days
Options exercisable	4 years 10 months 17 days
Vested and expected to vest	5 years 10 months 10 days
1996 Amended Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	5,000,000		5,000,000
2005 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance of awards (in shares)	11,450,000		11,450,000