Commitments and Contingencies - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended	4 Months Ended		12 Months Ended
	Aug. 31, 2015	Nov. 30, 2013	Sep. 30, 2016	Feb. 29, 2016	Oct. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Future commitments and obligations under operating lease
Lease term		139 months
Operating Leases
Free rent period		4 months
Tenant improvement allowance		$ 1,000,000
Payment of tenant improvement allowance		10 months
Increase (decrease) in monthly operating lease rent payment				$ 49,000	$ (49,000)
Payments for rent						$ 2,400,000
Future commitments and obligations under capital lease
Depreciation expense						$ 7,141,000	$ 7,314,000	$ 10,220,000
Notes Payable to Banks
Future commitments and obligations under operating lease
Line of Credit Facility, Amount Outstanding									$ 25,000,000
Rate of interest (as a percent)									3.25%
Extinguishment of debt	$ 21,600,000
Camco Furnace
Future commitments and obligations under capital lease
Capital lease term of contract			3 years
Capital lease annual discount rate						16.70%
Lease agreement annual payments						$ 31,000
Capital lease option cancellation period						12 months
Depreciation expense						$ 8,000	$ 0
Accrued liabilities | Camco Furnace
Future commitments and obligations under capital lease
Current portion of capital lease obligations						23,000
Other long-term liabilities | Camco Furnace
Future commitments and obligations under capital lease
Non-current portion of capital lease obligations						$ 39,000
Sublease
Future commitments and obligations under operating lease
Lease term						3 years
Future annual rental payments from sublessee						$ 300,000