Information about Geographic Areas and Operating Segments - Revenue and Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Total revenue:
Total revenue	$ 18,848	$ 22,738	$ 41,689	$ 48,177
Long-lived assets:
Total long-lived assets	5,318		5,318		$ 5,351
North America [Member]
Total revenue:
Total revenue	17,728	21,291	39,498	45,359
Long-lived assets:
Total long-lived assets	1,064		1,064		1,025
Asia [Member]
Total revenue:
Total revenue	306	554	556	828
Long-lived assets:
Total long-lived assets	83		83		90
Europe [Member]
Total revenue:
Total revenue	814	$ 893	1,635	$ 1,990
Long-lived assets:
Total long-lived assets	$ 4,171		$ 4,171		$ 4,236