PROPERTY AND EQUIPMENT, NET (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Equipment	$ 30,411	$ 31,426
Purchased software	10,028	11,781
Furniture and fixtures	5,669	5,468
Leasehold improvements	2,249	2,073
Property and equipment, gross	48,357	50,748
Less accumulated depreciation	(38,051)	(41,022)
Property and equipment, net	10,306	9,726
Depreciation expense	$ 5,000	$ 5,500	$ 7,300