Note 12 - Stock-Based Compensation (Tables)

9 Months Ended

Dec. 29, 2013

Note 12 - Stock-Based Compensation (Tables) [Line Items]

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

	As of December29,2013		Nine Months Ended December29,2013
	Shares of Common Stock		Shares of Common Stock		Weighted Average Price per Share
Authorized to issue		4,500
Reserved for future issuance		1,379
Issued				13	$	11.47

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

	Three Months Ended				Nine Months Ended
	December29, 2013		December30, 2012		December29, 2013		December30, 2012
Intrinsic value of options exercised	$	805	$	304	$	2,699	$	879

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 31, 2013		732,204		$	7.73		1.72	$	7,688
Granted		469,995			11.83
Issued and released		(311,406	)		9.48
Cancelled		(33,666	)		9.55
Unvested at December 29, 2013		857,127		$	9.27		1.65	$	9,968
Vested and expected to vest, December 29, 2013		761,615					1.60	$	8,858

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

	Three Months Ended				Nine Months Ended
	December29, 2013		December30, 2012		December29, 2013		December30, 2012
Cost of sales	$	165	$	175	$	519	$	289
Research and development		566		328		1,395		437
Selling, general and administrative		1,826		986		5,353		2,284
Total Stock-based compensation expense	$	2,557	$	1,489	$	7,267	$	3,010

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

	December29, 2013
	Amount (in thousands)		Weighted Average Expected Remaining Period (in years)
Options	$	8,180		2.7
RSUs		5,322		2.3
Total Stock-based compensation expense	$	13,502

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

	Three Months Ended						Nine Months Ended
	December29, 2013			December30, 2012			December29, 2013			December30, 2012
Expected term of options (years)		4.5			4.4		4.4	–	4.5	4.2	–	4.5
Risk-free interest rate		1.01	%		0.5	%	0.60%	–	1.12%	0.5%	–	0.6%
Expected volatility		32	%		41	%	32%	–	35%	41%	–	42%
Expected dividend yield		–			–			–			–
Weighted average estimated fair value	$	3.74		$	2.81		$	3.56		$	2.76

Employee Stock Option [Member]

Note 12 - Stock-Based Compensation (Tables) [Line Items]

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 31, 2013		6,212,333		$	7.48		5.04	$	19,199	$	1,481
Granted		1,460,300			12.38
Exercised		(535,832	)		7.12
Forfeited		(522,341	)		7.89
Cancelled		(10,834	)		10.92
Balance at December 29, 2013		6,603,626		$	8.56		5.07	$	21,985	$	2,062
Vested and expected to vest, December 29, 2013		6,184,803		$	8.46		5.00	$	21,073
Vested and exercisable, December 29, 2013		2,197,258		$	7.40		3.67	$	9,544