15. Share-based Payments

Stock Options

The Company granted options to purchase 302,539 and 256,236 shares of common stock during the nine months ended December 31, 2019 and 2018, respectively. The cost associated with stock options is estimated using the Black-Scholes option-pricing model. This model requires the input of subjective assumptions including the expected volatility of the underlying stock and the expected holding period of the option. These subjective assumptions are based on both historical and other information. Changes in the values assumed and used in the model can materially affect the estimate of fair value.

The following assumptions were used to derive the weighted average fair value of the stock options granted:

	Nine Months Ended December 31,
	2019			2018
Weighted average risk free interest rate		1.76	%		2.83	%
Weighted average expected holding period (years)		5.70			5.94
Weighted average expected volatility		42.50	%		43.91	%
Weighted average expected dividend yield		-			-
Weighted average fair value of options granted	$	8.27		$	8.75

The following is a summary of stock option transactions:

	Number of Shares			Weighted Average Exercise Price
Outstanding at March 31, 2019		1,337,165		$	17.58
Granted		302,539		$	19.72
Exercised		(56,400	)	$	7.71
Forfeited		(37,298	)	$	25.80
Outstanding at December 31, 2019		1,546,006		$	18.16

At December 31, 2019, options to purchase 521,685 shares of common stock were unvested at the weighted average exercise price of $20.34.

At December 31, 2019, there was $3,473,000 of total unrecognized compensation expense related to unvested stock option awards. Compensation expense related to unvested stock option awards will be recognized over a weighted average vesting period of approximately 2.0 years.

Restricted Stock Units and Restricted Stock (collectively “RSUs”)

During the nine months ended December 31, 2019 and 2018, the Company granted 113,483 and 104,725 shares of RSUs with an estimated grant date fair value of $2,112,000 and $2,075,000, respectively, which was based on the closing market price on the grant date.

The following is a summary of non-vested RSUs:

	Number of Shares			Weighted Average Grant Date Fair Value
Outstanding at March 31, 2019		243,134		$	21.75
Granted		113,483		$	18.61
Vested		(150,032	)	$	21.61
Forfeited		(1,701	)	$	21.53
Outstanding at December 31, 2019		204,884		$	20.12

At December 31, 2019, there was $3,170,000 of unrecognized compensation expense related to these awards, which will be recognized over the remaining vesting period of approximately 2.0 years.