Note 11 - Stockholders' Equity |
6 Months Ended |
|---|---|
Jun. 30, 2019 | |
| Notes to Financial Statements | |
| Stockholders' Equity Note Disclosure [Text Block] | 1 1 . Stockholders’ Equity Common Stock ATM Agreement On May 9, 2019, the Company increased the aggregate offering price of shares of the Company’s common stock which may be offered and sold under the Controlled Equity OfferingSM Sales Agreement, or the ATM Agreement, with Cantor Fitzgerald & Co., or Cantor, as agent by $40.0 million. There were no sales of common stock under the ATM Agreement during the three and six months ended June 30, 2019. As of June 30, 2019, the Company may offer and sell shares of the Company’s common stock having an aggregate offering price of up to $46,564,331, which includes the amount that remained for sale under the ATM Agreement before the increase. |