Equity-Based Compensation Expense Included in Interim Condensed Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total equity-based compensation expense	$ 5,011	$ 5,920	$ 5,083
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total equity-based compensation expense	193	312	241
Research and development, net
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total equity-based compensation expense	2,027	2,014	1,810
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total equity-based compensation expense	909	1,311	1,036
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total equity-based compensation expense	$ 1,882	$ 2,283	$ 1,996