Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	$ 6,104	$ 5,198
Stock-based compensation (capitalized to) expensed from inventory	(12)	18
Total stock-based compensation expense	6,092	5,216
Cost of Revenues [Member]
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	105	29
Research and Development Expense [Member]
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	4,060	3,271
Selling General and Administrative [Member]
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	1,939	1,898
Stock Options [Member]
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	207	414
Restricted Stock Units [Member]
Summary of Stock-Based Compensation Expense of Stock Options and Restricted Stock Units
Stock-based compensation expense by type of grant	$ 5,897	$ 4,784