Summary of Stock-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 1,723	$ 1,473	$ 3,624	$ 2,675
Cost of Goods Sold
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	455	131	785	374
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	408	600	1,115	1,018
Selling and Marketing Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	587	344	960	582
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Allocated share based compensation expense	$ 273	$ 398	$ 764	$ 701