Summary of Significant Accounting Policies - Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 18,032	$ 16,748
Less — accumulated depreciation and amortization	(13,982)	(12,215)
Total property and equipment	4,050	4,533
Depreciation expense	1,900	1,900	$ 1,600
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 8,557	7,583
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	2 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 6,512	6,242
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Computer hardware and software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	7 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 2,406	2,304
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	1 year
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	10 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 438	438
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	15 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, at cost:	$ 119	$ 181