Stockholders' Equity - Components of Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Beginning Balance	$ 158,172	$ 143,814	$ 158,088	$ 151,600
Issuance of common stock under stock plans, net	6	875	1,059	4,150
Stock-based compensation expense	2,464	2,848	5,266	5,533
Cumulative effect adjustment due to adoption of new accounting pronouncement, net of tax			(157)
Net income (loss)	11,837	1,555	11,324	(11,761)
Other comprehensive income (loss)	930	594	(2,171)	164
Ending Balance	173,409	149,686	173,409	149,686
Common Stock [Member]
Beginning Balance	$ 234	$ 231	$ 233	$ 230
Beginning Balance, Shares	23,389,000	23,050,000	23,275,000	22,951,000
Issuance of common stock under stock plans, net			$ 1	$ 1
Issuance of common stock under stock plans, net, Shares	12,000	39,000	126,000	138,000
Ending Balance	$ 234	$ 231	$ 234	$ 231
Ending Balance, Shares	23,401,000	23,089,000	23,401,000	23,089,000
Additional Paid-in Capital [Member]
Beginning Balance	$ 220,308	$ 206,655	$ 216,454	$ 200,696
Issuance of common stock under stock plans, net	6	875	1,058	4,149
Stock-based compensation expense	2,464	2,848	5,266	5,533
Ending Balance	222,778	210,378	222,778	210,378
Retained Earnings [Member]
Beginning Balance	117,477	114,401	118,147	127,717
Cumulative effect adjustment due to adoption of new accounting pronouncement, net of tax			(157)
Net income (loss)	11,837	1,555	11,324	(11,761)
Ending Balance	129,314	115,956	129,314	115,956
Treasury Stock [Member]
Beginning Balance	$ (171,889)	$ (171,889)	$ (171,889)	$ (171,889)
Beginning Balance, Shares	4,631,000	4,631,000	4,631,000	4,631,000
Ending Balance	$ (171,889)	$ (171,889)	$ (171,889)	$ (171,889)
Ending Balance, Shares	4,631,000	4,631,000	4,631,000	4,631,000
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	$ (7,958)	$ (5,584)	$ (4,857)	$ (5,154)
Other comprehensive income (loss)	930	594	(2,171)	164
Ending Balance	$ (7,028)	$ (4,990)	$ (7,028)	$ (4,990)