Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			$ 43,392
Balance at end of period	$ 35,428		35,428
Foreign currency translation
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,458)	$ (1,139)	(1,574)	$ (1,568)
Total other comprehensive (loss) income	380	(111)	496	318
Balance at end of period	(1,078)	(1,250)	(1,078)	(1,250)
Available-for-sale marketable securities
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	7	9	6	12
Other comprehensive (loss) income	0	(5)	1	(8)
Balance at end of period	7	4	7	4
Total accumulated other comprehensive loss
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at end of period	$ (1,071)	$ (1,246)	$ (1,071)	$ (1,246)