Joint Venture and Related Party Transactions - Summarized Financial Data (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Current assets	$ 62,907				$ 42,290				$ 62,907	$ 42,290
Current liabilities	4,446				4,680				4,446	4,680
Noncurrent liabilities	956				226				956	226
Revenue	5,180	$ 5,576	$ 5,457	$ 5,580	5,016	$ 5,386	$ 5,798	$ 5,989	21,793	22,189	$ 25,658
Gross profit	3,129	$ 3,414	$ 3,363	$ 3,390	3,032	$ 3,288	$ 3,349	$ 3,573	13,296	13,242	17,227
Operating expenses									35,216	31,219	32,450
TVaura Mobile LLC [Member]
Related Party Transaction [Line Items]
Current assets	40				45				40	45
Current liabilities	$ 11				$ 10				11	10
Operating expenses									5	5	5
Net loss from continuing operations									$ (5)	$ (5)	$ (5)