Note 13 - Subsequent Events	12 Months Ended
Dec. 31, 2021
Notes to Financial Statements
Subsequent Events [Text Block]	13. Subsequent Events Related party transaction In January 2022, the Company entered into an investment agreement (the “Investment Agreement”)with Eshelman Ventures, LLC and, solely for purposes of Article IV and Article V of the Investment Agreement, Dr. Eshelman relating to the issuance of a pre-funded warrant to purchase up to 4,545,455 shares of the Company’s common stock, par value $0.0001 per share, at a price of $2.20 per share, which was the consolidated closing bid price of the Company’s Common Stock on The Nasdaq on December 31, 2021, for an aggregate purchase price of $10 million. The closing of the transaction occurred on January 5, 2022. Pursuant to the terms of the Investment Agreement, the Company was required to file a registration statement registering the shares of common stock underlying the pre-funded warrant. The registration statement was filed on January 5, 2022 and declared effective by the SEC on January 18, 2022. At the Market Offering Program From January 1, 2022 to March 15, 2022, the Company sold 54,763 shares for proceeds net of discounts and offering costs of $0.1 million under the Equity Distribution Agreement. Registered Direct Offering and Related Party Transaction On March 31, 2022, the Company closed a registered direct offering of its common stock with a single healthcare-focused institutional investor and Eshelman Ventures, LLC, a related party, pursuant to which the Company issued 3,185,216 shares of common stock, 1,665,025 pre-funded warrants and common stock warrants to purchase up to 4,850,241 shares of common stock in a registered direct offering priced at-the-market under Nasdaq rules. The purchase price per share and accompanying common stock warrant was $2.005 for the institutional investor and $2.325 for Eshelman Ventures, LLC. The purchase price per pre-funded warrant and accompanying common stock warrant was $2.004 for the institutional investor The net proceeds from the offering was $9.3 million, including underwriting discounts, commission and offering expenses. The common stock warrants issued to the institutional investor are exercisable immediately, will expire five years from the exercisable date and will have an exercise price of $1.88 per share. The common stock warrants issued to Eshelman Ventures, LLC will be exercisable upon the approval by the stockholders of the Company of previously issued securities, will expire five years following the issuance date and will have an exercise price of $2.20 per share. The Company could receive additional gross proceeds of $9.4 million, if the warrants are fully exercised.

Note 13 - Subsequent Events

12 Months Ended

Dec. 31, 2021

13. Subsequent Events

Related party transaction

In January 2022, the Company entered into an investment agreement (the “Investment Agreement”)with Eshelman Ventures, LLC and, solely for purposes of Article IV and Article V of the Investment Agreement, Dr. Eshelman relating to the issuance of a pre-funded warrant to purchase up to 4,545,455 shares of the Company’s common stock, par value $0.0001 per share, at a price of $2.20 per share, which was the consolidated closing bid price of the Company’s Common Stock on The Nasdaq on December 31, 2021, for an aggregate purchase price of $10 million. The closing of the transaction occurred on January 5, 2022. Pursuant to the terms of the Investment Agreement, the Company was required to file a registration statement registering the shares of common stock underlying the pre-funded warrant. The registration statement was filed on January 5, 2022 and declared effective by the SEC on January 18, 2022.

At the Market Offering Program

From January 1, 2022 to March 15, 2022, the Company sold 54,763 shares for proceeds net of discounts and offering costs of $0.1 million under the Equity Distribution Agreement.

Registered Direct Offering and Related Party Transaction

On March 31, 2022, the Company closed a registered direct offering of its common stock with a single healthcare-focused institutional investor and Eshelman Ventures, LLC, a related party, pursuant to which the Company issued 3,185,216 shares of common stock, 1,665,025 pre-funded warrants and common stock warrants to purchase up to 4,850,241 shares of common stock in a registered direct offering priced at-the-market under Nasdaq rules. The purchase price per share and accompanying common stock warrant was $2.005 for the institutional investor and $2.325 for Eshelman Ventures, LLC. The purchase price per pre-funded warrant and accompanying common stock warrant was $2.004 for the institutional investor The net proceeds from the offering was $9.3 million, including underwriting discounts, commission and offering expenses. The common stock warrants issued to the institutional investor are exercisable immediately, will expire five years from the exercisable date and will have an exercise price of $1.88 per share. The common stock warrants issued to Eshelman Ventures, LLC will be exercisable upon the approval by the stockholders of the Company of previously issued securities, will expire five years following the issuance date and will have an exercise price of $2.20 per share. The Company could receive additional gross proceeds of $9.4 million, if the warrants are fully exercised.