Note 12 - Stock-based Compensation (Tables)

6 Months Ended

Sep. 27, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity [Table Text Block]

	As of September 27, 2015		Six Months Ended September 27, 2015
	Shares of Common Stock		Shares of Common Stock		Weighted Average Price per Share
Authorized to issue		4,500
Reserved for future issuance		1,334
Issued				12	$	9.45

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Outstanding			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)		In-the-money Options Vested and Exercisable (in thousands)
Balance at March 29, 2015		7,609,622		$	8.77		4.86	$	14,377		2,850
Granted		885,500			6.36
Exercised		(201,767	)		6.75
Cancelled		(135,253	)		8.05
Forfeited		(386,020	)		9.72
Balance at September 27, 2015		7,772,082		$	8.51		4.64	$	306		442
Vested and expected to vest, September 27, 2015		7,227,691		$	8.50		4.54	$	282
Vested and exercisable, September 27, 2015		3,872,013		$	8.04		3.64	$	193

Schedule of Cash Proceeds Received from Share-based Payment Awards [Table Text Block]

	Three Months Ended				Six Months Ended
	September 27, 2015		September 28, 2014		September 27, 2015		September 28, 2014
Intrinsic value of options exercised	$	172	$	426	$	598	$	856

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

	Shares			Weighted Average Grant- Date Fair Value		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Unvested at March 29, 2015		1,072,925		$	10.26		1.50	$	11,051
Granted		230,595			9.93
Issued and released		(352,009	)		9.84
Cancelled		(59,691	)		10.63
Unvested at September 27, 2015		891,820		$	10.32		1.27	$	5,413
Vested and expected to vest, September 27, 2015		739,170					1.18	$	4,487

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended				Six Months Ended
	September 27, 2015		September 28, 2014		September 27, 2015		September 28, 2014
Cost of sales	$	85	$	227	$	172	$	487
Research and development		205		870		654		1,682
Selling, general and administrative		1,162		2,503		2,563		4,558
Total Stock-based compensation expense	$	1,452	$	3,600	$	3,389	$	6,727

Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block]

	September 27, 2015
	Amount (in thousands)		Weighted Average Expected Remaining Period (in years)
Options	$	7,413		2.18
Performance Options		263		1.31
RSUs		3,070		1.77
PRSUs		1,034		1.52
Total Unrecognized Stock-based compensation expense	$	11,780