STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of RSUs granted and unvested

A summary of RSU activity is as follows:

	Number of RSUs		Weighted Average Fair Value Per Unit
RSUs granted and unvested at January 1, 2019	191,868		$	14.98
RSUs granted during 2019	94,558		13.88
RSUs vested during 2019	(150,250	)	14.98
RSUs forfeited during 2019	—		—
RSUs granted and unvested at December 31, 2019	136,176		$	14.21

Schedule of RSAs granted and unvested

A summary of RSA activity is as follows:

	Number of RSAs		Weighted Average Fair Value Per Unit
RSAs granted and unvested at January 1, 2019	4,939,419		$	12.37
RSAs granted during 2019	2,678,047		14.96
RSAs vested during 2019	(1,066,293	)	12.66
RSAs forfeited during 2019	(541,918	)	12.08
RSAs granted and unvested at December 31, 2019	6,009,255		$	13.51

Schedule of stock option activity

Stock option activity is as follows:

	Number of Shares Outstanding		Weighted- Average Exercise Price		Weighted- Average Grant-date Fair Value of Underlying Common Stock		Weighted- Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Balance at January 1, 2019	857,084		$	7.63			4.3	$	5,616
Stock options granted during 2019	—		$	—	$	—
Stock options exercised during 2019	(547,964	)	$	7.60
Stock options canceled during 2019	(5,845	)	$	9.94
Balance at December 31, 2019	303,275		$	7.63			4.4	$	3,393
Exercisable at December 31, 2019	303,275		$	7.63			4.4	$	3,393
Vested and expected to vest at December 31, 2019	303,275		$	7.63			4.4	$	3,393

Schedule of ESPP activity

The following table summarizes the ESPP activity during the years shown:

	Year Ended December 31,
	2019		2018		2017
Shares purchased and issued	92,738		90,084		49,247
Weighted average discounted price per share	$	12.64	$	9.74	$	11.08
Stock-based compensation expense (in thousands)	$	234	$	141	$	154