Note 12 - Stock-based Compensation (Tables)

9 Months Ended

Dec. 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 December 28, 2014		Nine Months Ended December 28, 2014
	Shares of Common Stock		Shares of Common Stock		Weighted Average Price per Share
Authorized to issue		4,500
Reserved for future issuance		1,352
Issued				21	$	10.11

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		2,517,178			8.64
Exercised		(523,193	)		6.85
Cancelled		(183,895	)		12.76
Forfeited		(981,008	)		10.49
Balance at December 28, 2014		8,042,840		$	8.74		4.97	$	15,344		2,959
Vested and expected to vest, December 28, 2014		7,487,866		$	8.66		4.88	$	14,864
Vested and exercisable, December 28, 2014		3,361,788		$	7.64		3.81	$	9,629

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

	Three Months Ended				Nine Months Ended
	December 28, 2014		December 29, 2013		December 28, 2014		December 29, 2013
Intrinsic value of options exercised	$	668	$	805	$	1,524	$	2,699

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		337,022			9.27
Issued and released		(230,553	)		10.65
Cancelled		(178,663	)		12.05
Unvested at December 28, 2014		1,104,932		$	10.31		1.40	$	11,370
Vested and expected to vest, December 28, 2014		962,572					1.32	$	9,905

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

	Three Months Ended				Nine Months Ended
	December 28, 2014		December 29, 2013		December 28, 2014		December 29, 2013
Cost of sales	$	496	$	165	$	983	$	519
Research and development		442		566		2,124		1,395
Selling, general and administrative		3,284		1,826		7,842		5,353
Total Stock-based compensation expense	$	4,222	$	2,557	$	10,949	$	7,267

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

	December 28, 2014
	Amount (in thousands)		Weighted Average Expected Remaining Period (in years)
Options	$	10,338		2.45
Performance Options		456		1.69
RSUs		7,051		1.89
PRSUs		1,329		1.98
Total Unrecognized Stock-based compensation expense	$	19,174

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

	Three Months Ended				Nine Months Ended
	December 28, 2014		December 29, 2013		December 28, 2014		December 29, 2013
Expected term of options (years)		4.67		4.50		4.53 – 4.70		4.40– 4.50
Risk-free interest rate		1.28%		1.01%		1.25% – 1.34%		0.6% – 1.12%
Expected volatility		33%		32%		32% –33%		32% –35%
Expected dividend yield		—		—		—		—
Weighted average estimated fair value	$	2.65	$	3.74	$	2.79	$	3.56