The following table presents stock-based compensation expenses included in our unaudited consolidated statements of operations and comprehensive loss (in thousands):


	Three Months Ended March 31,
	2023		2022
Cost of services and other revenue	$	4	$	5
Research and development		61		82
Selling and marketing		25		96
General and administrative		245		247
Stock-based compensation expense	$	335	$	430

Stock Options - We did not grant stock options in the three months ended March 31, 2023 or 2022.

Unrestricted Stock Grants - Our 2001 Nonqualified Stock Plan permits us to grant shares of unrestricted shares of stock to our directors, officers, and employees. Stock-based compensation expense for stock grants is determined based on the fair market value of our stock on the date of grant, provided the number of shares in the grant is fixed on the grant date.

We granted 134,211 and issued 61,462 shares of unrestricted stock to directors, officers, and employees during the three months ended March 31, 2023. Of the shares granted in the three months ended March 31, 2023, they are scheduled to be issued in two equal installments shortly after June 30, 2023 and December 31, 2023.

We granted 107,921 and issued 28,278 shares of unrestricted stock to directors, officers, and employees during the three months ended March 31, 2022. Of the shares granted in the three months ended March 31, 2022, 61,460 were issued shortly after June 30, 2022 and 46,461 were issued shortly after December 31, 2022.

Share Purchases - On March 1, 2022, our Board of Directors authorized a new stock repurchase program pursuant to which we may purchase up to $10.0 million of our common stock, of which $1.7 million has been repurchased as of March 31, 2023. During the three months ended March 31, 2023 and 2022 we purchased 190,908 and zero shares of our common stock, respectively. The shares may be purchased from time to time in the open market or through privately negotiated transactions at management’s discretion, depending upon market conditions and other factors. The authorization to repurchase shares of our common stock expires on December 31, 2023. Repurchases will be made under the program using our own cash resources and will be in accordance with Rule 10b5-1 under the Securities Exchange Act of 1934, and other applicable laws, rules and regulations, which may permit repurchases to occur during periods when we might otherwise be precluded from making purchases under insider trading laws or company policy. The program does not obligate us to acquire any particular amount of common stock and the program may be modified or suspended at any time at our Board of Director’s discretion.