On July 23, 2018, the Company filed a prospectus and prospectus supplement (the “2018 Prospectus”) under which the Company may offer and sell, from time to time, pursuant to an equity distribution agreement with Piper Jaffray & Co., up to $9.8 million in shares of its common stock. As of December 31, 2019, 25,218 shares have been sold under the 2018 Prospectus for gross proceeds of approximately $110,000. As of December 31, 2019, $8.7 million of the $9.8 million shares of common stock remains available to be offered and sold under the 2018 Prospectus.

On April 30, 2019, the Company agreed to sell in a registered direct offering, an aggregate 3,449,112 shares of its common stock to certain investors for gross proceeds of approximately $10.7 million under its effective shelf registration statement on Form S-3 (File No. 333-226286). In a concurrent private placement, the Company also agreed to issue to such investors Series A warrants to purchase up to 3,449,112 shares of its common stock at an exercise price of $4.00 with a term of eighteen months and Series B warrants to purchase up 3,449,112 shares of its common stock at an exercise price of $4.00 with a term of five years. The Series B warrants become exercisable only upon the exercise of the Series A warrants. In addition, the Company agreed to issue to H.C. Wainwright & Co., LLC, the placement agent for the transaction, warrants to purchase up to 172,456 shares of common stock. The placement agent warrants have substantially the same terms as the Series A Warrants, except that the placement agent warrants will have an exercise price equal to $3.86875 and will expire on April 30, 2024. We refer to the registered direct offering and the concurrent private placement collectively as the “2019 Equity Offering”.

All the warrants issued in connection with the 2019 Equity Offering contained put options that allow the holders of the warrants the right to receive, for each warrant share that would have been issuable upon an exercise immediately prior to the occurrence of an effective change in control event defined as a fundamental transaction, the number of shares of common stock of the successor or acquiring corporation or of the Company, if it is the surviving corporation, and any additional consideration receivable as a result of such fundamental transaction by a holder of the number of shares of common stock for which this warrant is exercisable immediately prior to such fundamental transaction. The Company evaluated the embedded put option contained in the warrants under the guidance of Accounting Standards Codification (“ASC”) 815, Derivatives and Hedging, and concluded that the requirements for contingent exercise provisions as well as the settlement provision for scope exception in ASC 815-10-15-74 has been met. Accordingly, the put options contained in the warrants were not bi-furcated and accounted for as freestanding derivative instruments.

As of December 31, 2019, a total of 7,070,680 warrants were available for exercise.

	Rollforward of Warrant Activity
	Registered direct warrants, series A		Registered direct warrants, series B		Registered direct warrants, placement agent		Total
Balance as of January 1, 2019	—		—		—		—
Warrants issued		3,449,112		3,449,112		172,456		7,070,680
Warrants exercised	—		—		—		—
Warrants expired	—		—		—		—
Balance as of December 31, 2019		3,449,112		3,449,112		172,456		7,070,680