CAPITAL STOCK (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Stock option plans

Information with respect to options granted under all stock option plans for the year ended December 31, 2019 was as follows:

	Total Shares		Weighted- Average Exercise Price	Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Options outstanding at January 1, 2019	891,892		$8.46
Granted	—		$—
Exercised	(70,006	)	$7.39
Forfeited or canceled	(256,886	)	$10.70
Options outstanding at December 31, 2019	565,000		$7.57	1.17	$571
Options vested at December 31, 2019 or expected to vest	565,000		$7.57	1.17	$571
Options exercisable at December 31, 2019	565,000		$7.57	1.17	$571

No options were granted during the years ended December 31, 2019, 2018, and 2017.

Non-vested restricted stock and restricted stock units

Information with respect to non-vested restricted stock units for the year ended December 31, 2019 was as follows:

	Non-Vested Restricted Stock Units
	Total Shares		Weighted- Average Grant-Date Fair Value	Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Non-vested at January 1, 2019	2,944,819		$4.91
Granted	1,731,579		$7.28
Vested	(1,658,270	)	$4.89
Forfeited	(375,930	)	$5.42
Non-vested at December 31, 2019	2,642,198		$6.40	0.95	$22,644
Expected to vest	2,642,198		$6.40	0.95	$22,644

Employee stock purchase plan

The following table sets forth the weighted-average key assumptions and fair value results for shares issued under the ESPP during the years ended December 31, 2019, 2018, and 2017:

	Year Ended December 31,
	2019	2018	2017
Expected dividend yield	0.00%	0.00%	0.00%
Risk-free interest rate	2.37%	1.85%	0.83%
Expected volatility	48.6%	55.3%	62.0%
Expected life (in years)	0.49	0.50	0.49
Weighted-average fair value of shares issued (per share)	$1.04	$0.94	$0.86

The following table sets forth the quantities and average prices of shares issued under the ESPP for the years ended December 31, 2019, 2018, and 2017:

	Year Ended December 31,
	2019	2018	2017
Shares issued under the ESPP	69,179	117,653	96,507
Average price of shares issued	$7.48	$4.22	$4.53

Allocated share-based compensation expense

Stock-based compensation was included in the following captions in our consolidated statements of operations for the years ended December 31, 2019, 2018, and 2017, respectively (in thousands):

	Year Ended December 31,
	2019		2018		2017
Cost of products revenues	$	343	$	128	$	53
Cost of service revenues	274		194		189
Research and development expenses	1,068		667		694
Marketing and selling expenses	1,797		1,540		1,944
General and administrative expenses	4,476		3,729		5,431
Total	$	7,958	$	6,258	$	8,311