Share-Based Compensation - Expense (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 15, 2015	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense		$ 1,066	$ 1,033	$ 2,129	$ 2,363
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition				2 years 2 months 13 days
Value of shares grant as compensation	$ 2,000			$ 497
Cost of Sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense		114	151	243	320
Selling, General and Administrative Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense		746	602	1,461	1,467
Research and Development Expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Total share-based compensation expense		206	$ 280	$ 425	$ 576
Restricted Stock [Member]
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				703,700	513,700
Stock Appreciation Rights (SARs) [Member]
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				467,000	260,000
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		$ 9,100		$ 9,100