Stockholders' Equity - Schedule of Share Based Compensation Expense (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
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	$ 2,819	$ 2,159	$ 7,835	$ 5,994
Property and equipment	39		102
Total share based compensation	2,858	2,159	7,937	5,994
Marketing and Selling [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	1,257	1,003	3,553	2,753
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	620	501	1,747	1,405
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share based compensation, Total expensed	$ 942	$ 655	$ 2,535	$ 1,836