Stock-based compensation expense is included in the following captions of the unaudited consolidated statements of comprehensive loss (in thousands):

	Three Months Ended
	May 31,
	2017		2016
Cost of revenues	$	138	$	64
Research and development		234		181
Selling		386		295
General and administrative		1,059		1,444
	$	1,817	$	1,984

Changes in the Company’s outstanding stock options during the three months ended May 31, 2017 were as follows (options in thousands):

			Weighted
	Number of		Average
	Options		Exercise
Outstanding at February 28, 2017	955		$	8.60
Granted	-			-
Exercised	(30	)		3.21
Forfeited or expired	-			-
Outstanding at May 31, 2017	925		$	8.78
Exercisable at May 31, 2017	594		$	5.12

Changes in the Company’s outstanding restricted stock shares, performance stock units (“PSUs”) and restricted stock units (“RSUs”) during the three months ended May 31, 2017 were as follows (restricted shares, PSUs and RSUs in thousands):

	Number of
	Restricted		Weighted
	Shares,		Average
	PSUs and		Grant Date
	RSUs		Fair Value
Outstanding at February 28, 2017	1,239		$	15.94
Granted	31			17.94
Vested	(29	)		16.34
Forfeited	(43	)		15.65
Outstanding at May 31, 2017	1,198		$	16.00

During the three months ended May 31, 2017, the Company retained 9,602 shares of the vested RSUs to satisfy the minimum required statutory amount of employee withholding taxes.

As of May 31, 2017, there was $15.0 million of total unrecognized stock-based compensation cost related to outstanding nonvested equity awards that is expected to be recognized as expense over a weighted-average remaining vesting period of 2.7 years.