Information about Operating Segments and Geographic Areas - Revenue and Long-Lived Assets by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Total revenue:
Total revenue	$ 15,366	$ 14,641	$ 14,180	$ 15,096	$ 16,839	$ 16,694	$ 19,203	$ 20,678	$ 59,283	$ 73,414
Long-lived assets:
Total long-lived assets	2,533				1,991				2,533	1,991
North America [Member]
Total revenue:
Total revenue									50,110	69,088
Long-lived assets:
Total long-lived assets	2,016				1,578				2,016	1,578
Asia [Member]
Total revenue:
Total revenue									7,150	1,271
Long-lived assets:
Total long-lived assets	177				91				177	91
Europe [Member]
Total revenue:
Total revenue									2,023	3,055
Long-lived assets:
Total long-lived assets	$ 340				$ 322				$ 340	$ 322