Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period			$ 58,974
Balance at end of period	$ 52,408		52,408
Foreign currency translation
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	(1,250)	$ (535)	(1,568)	$ (471)
Total other comprehensive (loss) income	57	(642)	375	(706)
Balance at end of period	(1,193)	(1,177)	(1,193)	(1,177)
Available-for-sale marketable securities
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at beginning of period	4	23	12	23
Other comprehensive (loss) income	4	(3)	(4)	(3)
Deferred income taxes	0	0	0	0
Total other comprehensive (loss) income	4	(3)	(4)	(3)
Balance at end of period	8	20	8	20
Total accumulated other comprehensive loss
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance at end of period	$ (1,185)	$ (1,157)	$ (1,185)	$ (1,157)