During the three months ended March 31, 2023, the Company granted 179,905 RSUs which had a weighted average grant date fair value of $4.16 per share, of which 91,900 RSUs had a cliff vesting period of three years, 42,000 RSUs had a cliff vesting period of two years, and 46,005 RSUs had a vesting period of 25% annually over four years.

As of March 31, 2023, there was $0.4 million of unrecognized stock-based compensation expense related to options and PNQs, which is expected to be recognized over a weighted average period of approximately 2.47 years, and $13.9 million and $8.5 million of unrecognized stock-based compensation expense related to RSUs and Market RSUs, respectively, which is expected to be recognized over a weighted average period of approximately 2.30 and 1.08 years, respectively.

Total stock-based compensation expense recognized in the condensed consolidated statements of operations as cost of goods sold, cost of revenue – collaborations and services, research and development and selling, general and administrative expense was as follows (in thousands):


	Three Months Ended March 31,
	2023		2022
RSUs and options	$	3,478	$	2,644
Employee stock purchase plan		177		162
Total	$	3,655	$	2,806

The Company provides all employees, including executive officers, the ability to purchase common stock at a discount under the Company’s 2004 the ESPP. The ESPP is designed to comply with Section 423 of the Internal Revenue Code and provides all employees with the opportunity to purchase up to $25,000 worth of common stock (based on the undiscounted fair market value at the commencement of the offering period) each year at a purchase price that is the lower of 85% of the fair market value of the common stock on either the date of purchase or the commencement of the offering period. An employee may not purchase more than 5,000 shares of common stock on any purchase date. The executives’ rights under the ESPP are identical to those of all other employees.

There were approximately 0.4 million shares of common stock available for issuance under the ESPP as of March 31, 2023.