11. STOCKHOLDERS’ EQUITY, COMPREHENSIVE INCOME AND STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Aug. 31, 2018

Equity [Abstract]

Changes in the components of AOCI

    Changes in the components of AOCI, net of tax, were as follows (in thousands):

	Cumulative Translation Adjustments			Unrealized Loss on Investments, Net		Total
Balance at May 31, 2018	$	2,292		$	--	$	2,292
Other comprehensive (loss) income before reclassifications		(16	)		--		(16	)
Amounts reclassified out of AOCI		--			--		--
Other comprehensive (loss) income, net of tax		(16	)		--		(16	)
Balance at August 31, 2018	$	2,276		$	--	$	2,276

Compensation costs related to the Company's stock-based compensation

    The following table summarizes the stock-based compensation expense for the three months ended August 31, 2018 and 2017 (in thousands):

	Three Months Ended
	August 31,
	2018		2017
Stock-based compensation in the form of employee stock options, RSUs and ESPP purchase rights, included in:
Cost of sales	$	36	$	22
Selling, general and administrative		148		150
Research and development		72		44
Net effect on net (loss) income	$	256	$	216

Fair value assumptions for option valuation model

    The fair value of the Company’s stock options granted to employees for the three months ended August 31, 2018 and 2017 were estimated using the following weighted average assumptions in the Black-Scholes option valuation model:

	Three Months Ended
	August 31,
	2018			2017
Expected term (in years)		5			4
Volatility		0.74			0.78
Risk-free interest rate		2.75	%		1.75	%
Weighted average grant date fair value	$	1.48		$	2.27

Stock option and RSU transactions

    The following tables summarize the Company’s stock option and RSU transactions during three months ended August 31, 2018 (in thousands):

	Available
	Shares
Balance, May 31, 2018		1,812
Options granted		(441	)
RSUs granted		--
Shares cancelled		13
Shares expired		(11	)
Balance, August 31, 2018		1,373

Stock option transactions

    The following table summarizes the stock option transactions during the three months ended August 31, 2018 (in thousands, except per share data):

	Outstanding Options
				Weighted
	Number			Average		Aggregate
	of			Exercise		Intrinsic
	Shares			Price		Value
Balances, May 31, 2018		2,859		$	2.04	$	1,987
Options granted		441		$	2.40
Options cancelled		(13	)	$	1.64
Options exercised		(98	)	$	1.12
Balances, August 31, 2018		3,189		$	2.12	$	1,757
Options fully vested and expected to vest at August 31, 2018		3,156		$	2.12	$	1,746

Options outstanding

     The options outstanding and exercisable at August 31, 2018 were in the following exercise price ranges (in thousands, except per share data):

		Options Outstanding						Options Exercisable
		at August 31, 2018						at August 31, 2018
Range of Exercise Prices		Number Outstanding Shares		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Number Exercisable Shares		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Aggregate Intrinsic Value
$	0.59-$0.97		259		0.51	$	0.67		259		0.51	$	0.67
$	1.09-$1.36		507		1.46	$	1.28		506		1.46	$	1.28
$	1.68-$2.06		466		4.04	$	1.74		318		3.64	$	1.77
$	2.10-$2.81		1,695		4.34	$	2.44		1,130		3.26	$	2.47
$	3.46-$3.93		262		5.91	$	3.86		94		5.96	$	3.76
$	0.59-$3.93		3,189		3.66	$	2.12		2,307		2.72	$	1.96	$1,541