Stockholders' Equity (Tables)

9 Months Ended

Oct. 01, 2021

Stockholders Equity Note [Abstract]

Schedule of Compensation Cost

The cost that has been charged against income for stock-based compensation is set forth below (in thousands):

	Three Months Ended				Nine Months Ended
	October 1, 2021		October 2, 2020		October 1, 2021		October 2, 2020
Employee stock options	$	2,594	$	2,469	$	7,850	$	7,206
Restricted stock		109		119		507		273
Restricted stock units		700		415		2,048		1,238
Performance stock units		124		54		325		54
Nonemployee stock options		136		69		255		194
Total stock-based compensation expense	$	3,663	$	3,126	$	10,985	$	8,965

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The Company recorded stock-based compensation costs in the following categories (in thousands):

	Three Months Ended				Nine Months Ended
	October 1, 2021		October 2, 2020		October 1, 2021		October 2, 2020
Cost of sales	$	61	$	30	$	150	$	82
General and administrative		1,671		1,307		4,925		3,601
Selling and marketing		851		807		2,637		2,674
Research and development		1,080		982		3,273		2,608
Total stock-based compensation expense, net		3,663		3,126		10,985		8,965
Amounts capitalized as part of inventory		383		287		1,082		847
Total stock-based compensation expense, gross	$	4,046	$	3,413	$	12,067	$	9,812

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The risk-free rate is based on the U.S. Treasury yield curve corresponding to the expected term at the time of the grant.

	Three Months Ended						Nine Months Ended
	October 1, 2021			October 2, 2020			October 1, 2021			October 2, 2020
Expected dividend yield		0	%		0	%		0	%		0	%
Expected volatility		53	%		53	%		53	%		53	%
Risk-free interest rate		0.79	%		0.31	%		0.84	%		0.53	%
Expected term (in years)		5.38			5.72			5.38			5.72

Schedule of Share-based Compensation, Stock Options, Activity

A summary of stock option activity under the Plan for nine months ended October 1, 2021 is presented below:

	Stock Options (in 000’s)			Minimum Exercise Price		Maximum Exercise Price
Outstanding at January 1, 2021		3,418
Granted		268
Exercised		(1,089	)
Forfeited or expired		(27	)
Outstanding at October 1, 2021		2,570		$	5.34	$	154.96
Exercisable at October 1, 2021		1,864

Schedule of Share-based Compensation, Restricted Stock, RSUs and PSUs Activity

A summary of restricted stock, RSUs and PSUs activity under the Plan for the nine months ended October 1, 2021 is presented below (shares in thousands):

	Restricted Stock			RSUs			PSUs
Unvested at January 1, 2021		11			122			15
Granted		3			63			—
Vested		(11	)		(54	)		(5	)
Forfeited or expired		—			—			—
Unvested at October 1, 2021		3			131			10