Note 9 — Warrants

The Company had 2,714,858 warrants outstanding at March 31, 2020 with a weighted average exercise price of $1.70 per share, down from 3,331,506 warrants outstanding at December 31, 2019. During the three months ended March 31, 2020, warrants to purchase 616,648 shares of common stock expired.

At March 31, 2020, all warrants are exercisable, although the warrants held by each of the Company’s four largest beneficial owners may be exercised only to the extent that the total number of shares of common stock then beneficially owned by such shareholder does not exceed 9.99% of the outstanding shares of the Company’s common stock.