Stockholders' Equity - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 86
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income before reclassifications	29
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net current period other comprehensive income (loss)	29
Ending Balance	115
Unrealized Gains and Losses on Available-for Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(15)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income before reclassifications	8
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net current period other comprehensive income (loss)	8
Ending Balance	(7)
Foreign Currency Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	101
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Other comprehensive income before reclassifications	21
Amounts reclassified from accumulated other comprehensive income (loss)
Net current period other comprehensive income (loss)	21
Ending Balance	$ 122