Note 12 - Stock-Based Compensation (Tables)

6 Months Ended

Sep. 28, 2014

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 28,2014		Six Months Ended September 28,2014
	Shares of Common Stock		Shares of Common Stock		Weighted Average Price per Share
Authorized to issue		4,500
Reserved for future issuance		1,359
Issued				13	$	10.94

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 30, 2014		7,213,848		$	8.98		5.02	$	21,301		2,170
Granted		2,117,738			8.60
Exercised		(243,176	)		6.83
Cancelled		(123,023	)		12.94
Forfeited		(545,080	)		10.29
Balance at September 28, 2014		8,420,307		$	8.80		4.93	$	9,232		4,454
Vested and expected to vest, September 28, 2014		7,446,743		$	8.66		4.84	$	9,063
Vested and exercisable, September 28, 2014		3,285,957		$	7.47		3.83	$	6,345

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

	Three Months Ended				Six Months Ended
	September 28, 2014		September 29, 2013		September 28, 2014		September 29, 2013
Intrinsic value of options exercised	$	426	$	1,072	$	856	$	1,894

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 30, 2014		1,177,126		$	10.94		1.62	$	13,784
Granted		204,697			9.50
Issued and released		(221,219	)		10.71
Cancelled		(89,998	)		14.35
Unvested at September 28, 2014		1,070,606		$	10.42		1.48	$	9,710
Vested and expected to vest, September 28, 2014		931,862					1.42	$	8,452

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

	Three Months Ended				Six Months Ended
	September 28, 2014		September 29, 2013		September 28, 2014		September 29, 2013
Cost of sales	$	227	$	212	$	487	$	354
Research and development		870		689		1,682		829
Selling, general and administrative		2,503		2,722		4,558		3,527
Total Stock-based compensation expense	$	3,600	$	3,623	$	6,727	$	4,710

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

	September 28, 2014
	Amount (in thousands)		Weighted Average Expected Remaining Period (in years)
Options	$	9,898		2.44
Performance Options		531		1.96
RSUs		4,896		1.99
PRSUs		1,894		2.22
Total Unrecognized Stock-based compensation expense	$	17,219

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Three Months Ended						Six Months Ended
	September 28, 2014			September 29, 2013			September 28, 2014			September 29, 2013
Expected term of options (years)		4.70			4.44			4.50- 4.70			4.40- 4.44
Risk-free interest rate		1.34	%		1.12	%		1.30% - 1.34	%		0.6%- 1.12
Expected volatility		32	%		33	%		32	%		33% -35	%
Expected dividend yield		─			─			─			─
Weighted average estimated fair value	$	2.89		$	3.70		$	2.86		$	3.49