Stock-Benefit Plans and Equity Transactions (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Total Stock Based Compensation

The Company has stock-based compensation plans under which it grants stock options, RSUs, and PRSUs to officers, directors and third parties. Total stock-based compensation for the periods presented were as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2022		2021		2022		2021
Cost of sales	$	449	$	235	$	705	$	330
Research and development		1,362		664		2,334		1,162
Sales, general and administrative		7,392		10,597		16,348		14,478
Total	$	9,203	$	11,496	$	19,387	$	15,970

Schedule of Assumptions used to Estimate Fair Value of Stock Options Granted and Stock Purchase Rights under ESPP

The Company estimates the fair value of shares issued to employees under the ESPP using the Black-Scholes option-pricing model. The assumptions used to estimate the fair value of stock options granted and stock purchase rights under the ESPP are as follows:

	Three and Six Months Ended
	June 30,
	2022		2021
Risk-free interest rate	0.07% - 1.54%		0.04% - 0.10 %
Expected dividend yield		—		—
Expected term (years)		0.50		0.50
Volatility	50.29% - 64.53%		49.98% - 78.51%

Summary of All Outstanding Warrants for Common Stock

A summary of all outstanding warrants for common stock as of June 30, 2022, were as follows (in thousands, except for strike price data):

	Number of Warrants		Strike Price		Expiration
2018 PIPE Warrants		8,354	$	3.50	May 2023
SafeOp Surgical Merger Warrants		938	$	3.50	May 2023
2018 Squadron Medical Warrants		845	$	3.15	May 2027
2019 Squadron Medical Warrants		4,839	$	2.17	May 2027
2020 Squadron Medical Warrants		1,076	$	4.88	May 2027
Executive Warrants		1,327	$	5.00	December 2022
Other(1)		121	$	5.37	Various through February 2026
Total		17,500

(1)Weighted-average strike price.