STOCK BASED COMPENSATION - Expense Resulting from Stock Option Awards and ESPP (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 5,114	$ 5,254	$ 16,671	$ 16,158
Stock Options [Member] | Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	26	24	53	69
Stock Options [Member] | Selling, general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4,287	4,416	13,624	13,795
Restricted Stock Units (RSUs) [Member] | Selling, general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	302	382	1,260	1,103
ESPP [Member] | Selling, general and administrative expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 499	$ 432	$ 1,734	$ 1,191