Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Summary of the company's stock option activity and related information

A summary of stock option activity and related information is as follows:

	Options	Weighted Average Exercise Price			Weighted average remaining contractual term (years)	Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2019	2,844,164		$	30.41	7.9	$	124,585
Granted	214,690		$	85.03
Exercised	(493,965)		$	7.76		$	35,400
Forfeited	(50,088)		$	40.11
Outstanding at September 30, 2020	2,514,801		$	39.33	7.7	$	225,640
Exercisable at September 30, 2020	1,098,248		$	16.30	6.3	$	123,823

Schedule of stock compensation recognized, before taxes

Total stock-based compensation recognized, before taxes, during the three and nine months ended September 30, 2020 and 2019, is as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Cost of goods sold	$	36	$	33	$	122	$	85
Research and development	535		168		1,252		492
Selling, general and administrative	2,740		1,323		7,589		3,727
Total stock-based compensation	$	3,311	$	1,524	$	8,963	$	4,304

Summary of weighted average assumptions for fair value of options granted

The fair value of options granted to employees and non-employee directors during the nine months ended September 30, 2020 and 2019 was estimated as of the grant date using the Black-Scholes option pricing model using the following assumptions:

	Nine Months Ended
	September 30,
	2020	2019
Expected life (years)	5.50 - 6.25	5.50 - 6.25
Expected volatility	42.3 - 49.3%	47.7 - 50.6%
Risk-free interest rate	0.36 - 1.42%	1.55 - 2.63%
Dividend yield	0.0%	0.0%
Weighted average fair value	$38.33	$29.30