Share-Based Compensation - Expense (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			513,700	616,000
Total share-based compensation expense	$ 1,033,000	$ 1,234,000	$ 2,363,000	$ 3,868,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			2 years 2 months 17 days
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	151,000	189,000	320,000	374,000
Selling, General and Administrative Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	602,000	666,000	1,467,000	2,760,000
Research and Development Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense	280,000	379,000	576,000	734,000
Stock Options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 6,900,000		$ 6,900,000