Stock Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Valuation Assumptions

For performance-based restricted stock units granted during 2020 and 2019 valued using the Monte Carlo Simulation valuation model, we used the following assumptions:

	Year ended December 31
	2020		2019
Risk-free interest rate	1.2	%	1.8% - 2.48%
Expected dividend yield	—	%	—	%
Term	3 years		3 years
Expected volatility	40.0	%	45.0	%
Weighted-average expected volatility	40.0	%	45.0	%

Schedule of Stock Option Activity

A summary of stock option activity and weighted average exercise prices follows:

	Options	Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value as of December 31, 2020
Outstanding at January 1, 2020	486,682	$	52.37
Granted	—	—
Forfeited	(34,605)	57.51
Exercised	(297,029)	49.60
Outstanding at December 31, 2020	155,048	$	56.53	2.3	$	2,187
Options exercisable at December 31, 2020	148,469	$	56.31	0.8	$	2,125

Schedule of Restricted Stock Activity

The following table summarizes the restricted stock and restricted stock unit activity and weighted-average grant date fair values for the year ended December 31, 2020:

	Shares	Weighted-Average Grant Date Fair Value
Non-vested at January 1, 2020	398,318	$	49.53
Granted	208,405	65.36
Forfeited	(56,850)	56.56
Vested	(172,426)	41.46
Non-vested at December 31, 2020	377,447	$	60.92

Share-based Payment Arrangement, Expensed and Capitalized, Amount

The following table summarizes total stock-based compensation expense for each of the line items on our consolidated statement of operations:

	Years ended December 31,
	2020		2019		2018
Cost of Sales
Product	$	356	$	628	$	477
Service	346		373		351
Total cost of sales	$	702	$	1,001	$	828
Operating Expenses
Selling, general and administrative	$	6,327	$	8,786	$	5,210
Research and development	1,285		1,282		1,583
Total operating expenses	$	7,612	$	10,068	$	6,793