Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$ 914
State	42
Income tax expense (benefit)	956
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Income tax expense/(benefit) computed at U.S federal statutory tax rate	5,240	$ 6,955	$ (32,286)
Permanent items	601	610	340
State income taxes	50	627	(4,772)
Change in valuation allowance	(4,849)	(10,604)	31,526
Uncertain income tax position	833	(960)	5,411
Research and development credits	(979)	(535)	(156)
Other	60	(125)	(63)
Deferred rate change		4,032
Income tax expense (benefit)	956
NOL carryforwards	91,800
NOL carryforwards after tax effect	34,600
Research and development credit carryforwards	5,500
Available NOL's	18,500
Available from 2015 to 2019	91,800
Research and development credit carryforward available in 2020 to 2021	5,500
Federal income taxes paid	0	0	0
Accrued penalties related to uncertain tax positions	100
Deferred tax assets:
Net operating loss carryforward	34,676	42,800
Deferred rent credit	532	506
Accrued compensation and non-qualified stock options	5,891	3,392
Deferred financing costs	188	244
Depreciation and amortization	291	474
Research and development credits	5,529	4,725
Capitalized overhead into inventory (UNICAP 263A)	543	675
Other	495	552
Valuation allowance	(47,526)	(49,914)
Net deferred tax asset	619	3,454
Deferred tax liability:
Debt discount on convertible notes	(509)	(3,454)
Depreciation	(110)
Net change in total valuation allowance	2,500
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at the beginning of the period	8,342	9,828	688
Gross (decreases) increases related to prior-year tax positions	(5)	(1,040)	23
Gross increases related to current-year tax positions	984	80	9,117
Gross decreases related to current-year tax prositions	(244)
Change in tax rates	(21)	(526)
Balance at the end of the period	9,056	$ 8,342	$ 9,828
Income tax expense	956
Minimum
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Available NOL's utilized per year in future years	7,800
Maximum
Reconciliation of the expected income tax benefit computed using the federal statutory income tax rate to the Company's effective income tax rate
Available NOL's utilized per year in future years	$ 20,300