Property and Equipment - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total cost	$ 67,649	$ 61,803
Less: Accumulated depreciation	(36,477)	(37,799)
Property and equipment, net	31,172	24,004
Land
Property, Plant and Equipment [Line Items]
Total cost	2,900	2,900
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Total cost	$ 18,383	15,295
Building and leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Building and leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	39 years
Production equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 19,075	19,849
Production equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Production equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Total cost	$ 6,780	7,985
Computers, equipment and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Computers, equipment and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 5,262	4,990
Furniture and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Furniture and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Vehicles
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Total cost	$ 1,057	675
Website development costs
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Total cost	$ 687	601
Capitalized internal-use software development costs
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Total cost	$ 3,695	3,695
Construction-in-process
Property, Plant and Equipment [Line Items]
Total cost	$ 9,810	$ 5,813