Note 12. Warrants

A summary of warrant activity for three months ended April 30, 2023 is as follows:

During the three months ended April 30, 2023, stock based compensation expense related to warrant grants was $641,000, which consisted of grants to employees of $338,000, directors of $237,000, and consultants of $66,000. During the three months ended April 30, 2022, stock based compensation expense related to warrant grants was $685,000, which consisted of grants to employees of $407,000, directors of $209,000, and consultants of $66,000.