Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2020

A summary of stock option activity under the 2011 Plan for the years ended December 31, 2020, 2019 and 2018 is as follows (intrinsic value in thousands):

	Number of Awards			Weighted Average Exercise Price		Weighted Average Fair Value		Weighted Average Remaining Contractual Life (in years)		Intrinsic Value
Outstanding, December 31, 2017		1,682,619		$	0.30	$	0.24		8.22	$	29
Granted		1,928,799			0.43		0.36
Exercised		(835,359	)		0.31		0.26				96
Cancelled		(87,532	)		0.31		0.26
Outstanding, December 31, 2018		2,688,527			0.39		0.31		8.95		190
Granted		1,901,837			1.48		1.19
Exercised		(409,893	)		0.31		0.26				560
Cancelled		(98,169	)		0.40		0.34
Outstanding, December 31, 2019		4,082,302			0.90		0.74		8.76		22,667
Granted		305,494			7.47		3.73
Exercised		(851,190	)		0.55		0.50				49,413
Cancelled		(99,821	)		8.39		3.62
Outstanding, December 31, 2020		3,436,785		$	1.36	$	0.98		8.05	$	295,331
Vested and exercisable at December 31, 2020		1,370,991		$	0.88	$	0.68		7.84	$	118,473
Vested and expected to vest at December 31, 2020		3,409,054		$	1.29	$	0.93		7.98	$	293,185

Schedule of Estimated Fair Value of Options and Restricted Stock Units Grant on Date of Grant

The fair value of each option grant under the 2011 Plan was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:

	Years Ended December 31,
	2020	2019	2018
Expected volatility	40.60%	53.5% - 93.4%	109.10%
Weighted-average volatility	40.60%	83.24%	109.10%
Common stock fair value (per share)	$7.88 - $9.05	$0.59 - $6.15	$0.31 - $0.43
Dividend yield	0.00%	0.00%	0.00%
Risk free interest rates	1.46% - 1.68%	1.67% - 2.44%	2.63% - 3.00%
Expected remaining term in years	5.90 - 6.07	5.02 - 7.00	6.01 - 6.06

Summary of RSU Activity

RSU activity under the 2020 Plan is set forth below (intrinsic value in thousands):

	Number of Awards			Weighted Average Fair Value		Intrinsic Value
Outstanding, December 31, 2019		—		$	—	$	—
Granted		227,963			58.68		13,356
Vested		(1,199	)		51.41		80
Cancelled		(4,200	)		51.41		232
Outstanding, December 31, 2020		222,564		$	58.86	$	19,428

Schedule of Total Compensation Cost for All Share-Based Payment Arrangements Recognized

Stock Based Compensation

Total compensation cost for all share-based payment arrangements recognized, including $560,000 of stock-based compensation expense related to the ESPP for the year ended December 31, 2020, was as follows (in thousands):

	Years Ended December 31,
	2020		2019		2018
Cost of goods sold	$	155	$	52	$	2
Research and development		592		99		70
Selling, general and administrative		2,776		354		176
	$	3,523	$	505	$	248

2020 Employee Stock Purchase Plan

Schedule of Estimated Fair Value of Options and Restricted Stock Units Grant on Date of Grant

The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model.

		Year ended December 31, 2020

Expected term (in years)		0.5
Expected volatility		49.23%
Dividend yield		0.00%
Risk free interest rate		0.11%

Restricted Stock Units

Schedule of Estimated Fair Value of Options and Restricted Stock Units Grant on Date of Grant

The following assumptions were used to calculate the fair value of these options and restricted stock units in the Monte Carlo simulation model at the grant date:

		Year ended December 31, 2019
Expected term (in years)		4.00
Expected volatility		50.00%
Dividend yield		0.00%
Risk free interest rate		2.41%