9. STOCK- BASED COMPENSATION (Tables)

12 Months Ended

Mar. 31, 2017

STOCK- BASED COMPENSATION

Summary of stock option activities

			Weighted
		Number of Shares	Average	Weighted
	Shares	Underlying	Remaining	Average
	Available for	Options	Contractual	Exercise		Intrinsic
	Grant	Outstanding	Life (Years)	Price		Value
Balance at March 31, 2014	5,585,500	6,143,980		$	5.13
Options reserved	1,377,699	—			—
Granted	(791,903)	791,903		$	5.20
Exercised	—	(119,085)		$	3.88	$	262,253
Forfeited	42,647	(42,647)		$	5.49
Balance at March 31, 2015	6,213,943	6,774,151		$	5.16
Options reserved	1,156,419	—			—
Granted	(969,913)	969,913		$	4.42
Exercised	—	(76,745)		$	4.19	$	46,977
Forfeited	31,614	(41,614)		$	4.82
Balance at March 31, 2016	6,432,063	7,625,705		$	5.08
Options reserved	1,085,818	—			—
Terminated plan	(705,699)	—			—
Granted	(1,362,798)	1,362,798		$	5.14
Exercised	—	(391,039)		$	3.96	$	855,160
Forfeited	14,801	(974,634)		$	5.53
Balance at March 31, 2017	5,464,185	7,622,830		$	5.09
Options vested and exercisable		4,731,902	4.00	$	5.04	$	17,365,055
Options vested and expected to vest		7,569,918	5.71	$	5.09	$	27,412,888

Schedule of options outstanding by exercise price

				Number of	Options Outstanding			Options Exercisable
				Shares	Weighted		Weighted Average		Weighted
				Underlying	Average		Remaining	Number	Average
				Options	Exercise		Contractual	Vested and	Exercise
Exercise Price				Outstanding	Price		Life (Years)	Exercisable	Price
$	2.43	-	3.40	789,595	$	3.22	4.39	558,137	$	3.14
$	3.43	-	4.00	1,157,919	$	3.80	3.04	1,042,275	$	3.83
$	4.17	-	4.81	840,645	$	4.42	4.92	750,395	$	4.41
$	4.90	-	4.99	1,424,681	$	4.97	8.13	293,928	$	4.91
$	5.13	-	5.28	798,098	$	5.23	8.06	90,030	$	5.19
$	5.34	-	6.00	768,984	$	5.75	5.27	728,336	$	5.76
$	6.16	-	6.54	887,513	$	6.35	6.30	584,903	$	6.43
$	6.61	-	6.86	635,822	$	6.78	5.92	364,325	$	6.74
$	7.00			206,193	$	7.00	3.34	206,193	$	7.00
$	9.20			113,380	$	9.20	3.84	113,380	$	9.20
				7,622,830	$	5.09	5.73	4,731,902	$	5.04

Summary of stock-based compensation expense by line item

	Year Ended March 31,
	2017		2016		2015
	(In thousands)
Cost of revenues	$	282	$	320	$	401
Research and development		980		858		941
Selling, general and administrative		615		672		735
Total	$	1,877	$	1,850	$	2,077

Schedule of weighted average assumptions

	Year Ended March 31,
	2017				2016				2015
	(In thousands)
Stock Option Plans:
Risk-free interest rate	1.12	-	1.95	%	1.41	-	1.57	%	1.47	-	1.70	%
Expected life (in years)	5.00						5.00				5.00
Volatility	33.3	-	35.4	%	36.3	-	38.0	%	40.4	-	44.8	%
Dividend yield			—	%			—	%			—	%
Employee Stock Purchase Plan:
Risk-free interest rate	0.38	-	0.45	%	0.09	-	0.15	%			0.05	%
Expected life (in years)	0.50						0.50				0.50
Volatility	30.8	-	39.6	%	26.3	-	27.9	%	30.8	-	38.0	%
Dividend yield			—	%			—	%			—	%