Note 12. Warrants

A summary of warrant activity for six months ended July 31, 2023 is as follows:

During the three months ended July 31, 2023, stock-based compensation expense related to warrant grants was $575,000, which consisted of grants to employees of $338,000 and directors of $237,000. During the six months ended July 31, 2023, stock-based compensation expense related to warrant grants was $1,215,000, which consisted of grants to employees of $675,000, directors of $474,000, and consultants of $66,000. During the three months ended July 31, 2022, stock-based compensation expense related to warrant grants was $589,000, which consisted of grants to employees of $317,000, directors of $209,000, and consultants of $63,000. During the six months ended July 31, 2022, stock-based compensation expense related to warrant grants was $1,274,000, which consisted of grants to employees of $724,000, directors of $418,000, and consultants of $132,000.