Share-based Compensation - Schedule of Share-Based Compensation by Line Item in Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	$ 1,730	$ 1,277	$ 4,103	$ 4,714
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	40	27	98	(249)
Sales and Marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	537	469	1,410	1,375
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	1,069	726	2,368	3,431
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share-based compensation expense	$ 84	$ 55	$ 227	$ 157