Warrants

As of March 31, 2020, the Company had the following potentially issuable shares of common stock related to unexercised warrants outstanding:



	Shares	Exercise price		Expiration date	Classification
Hercules Warrant	41,177	$	6.80	Q2 2023	Equity
2018 Public Offering Warrants	3,616,944	$	9.60	Q1 2023	Liability
Private Placement Warrants	932,812	$	4.52	Q1 2024	Equity
Pre-Funded Warrants	531,250	$	0.08	Q1 2039	Equity
	5,122,183

Hercules Warrant

The exercise price and the number of shares are subject to adjustment upon a merger event, reclassification of the shares of common stock, subdivision or combination of the shares of common stock or certain dividends payments. The Company determined that the Hercules Warrant should be equity classified in accordance with ASC 480, Distinguishing Liabilities from Equity ("ASC 480") for all periods presented.

2018 Public Offering Warrants

In January 2018, the Company entered into two underwriting agreements, the first relating to the public offering of 6,670,625 shares of the Company’s common stock, par value $0.001 per share, and accompanying warrants to purchase up to 3,335,313 shares of common stock (“2018 Public Offering Warrants”). The exercise price and the number of shares are subject to adjustment upon a merger event, reclassification of the shares of common stock, subdivision or combination of the shares of common stock or certain dividends payments. In the event of an “Acquisition,” defined generally to include a merger or consolidation resulting in the sale of 50% or more of the voting securities of the Company, the sale of all, or substantially all, of the assets or voting securities of the Company, or other change of control transaction, as defined in the 2018 Public Offering Warrants, the Company will be obligated to use its best efforts to ensure that the holders of the 2018 Public Offering Warrants receive new warrants from the surviving or acquiring entity (the “Acquirer”). The new warrants to purchase shares in the Acquirer shall have the same expiration date as the 2018 Public Offering Warrants and a strike price that is based on the proportion of the value of the Acquirer’s stock to the Company’s common stock. If the Company is unable, despite its best efforts, to cause the Acquirer to issue new warrants in the Acquisition as described above, then, if the Company’s stockholders are to receive cash in the Acquisition, the Company will settle the 2018 Public Offering Warrants in cash and if the Company’s stockholders are to receive stock in the Acquisition, the Company will issue shares of its common stock to each Warrant holder.

The Company determined that the 2018 Public Offering Warrants should be liability classified in accordance with ASC 480. As the 2018 Public Offering Warrants are liability-classified, the Company remeasures the fair value at each reporting date. The Company initially recorded the 2018 Public Offering Warrants at their estimated fair value of approximately $18.2 million. In connection with the Company's remeasurement of the 2018 Public Offering Warrants to fair value, the Company recorded income of approximately $0.8 million and expense of approximately $5.8 million for the three months ended March 31, 2020 and 2019, respectively. The fair value of the warrant liability is approximately $1.7 million and $2.5 million as of March 31, 2020 and December 31, 2019, respectively.

The following table details the assumptions used in the Monte Carlo simulation models used to estimate the fair value of the Warrant Liability as of March 31, 2020 and December 31, 2019, respectively:



	March 31, 2020			December 31, 2019
Stock price	$	1.72		$	2.07
Volatility	50.0% - 124.5%			50.0% - 116.6%
Remaining term (years)	2.8			3.1
Expected dividend yield	—			—
Risk-free rate	0.3		%	1.6		%
Annual acquisition event probability	30.0		%	20.0		%

Private Placement and Prefunded Warrants

The exercise price of the warrants is subject to appropriate adjustment in the event of stock dividends, subdivisions, stock splits, stock combinations, reclassifications, reorganizations or a change of control affecting our common stock. The Company determined that the Private Placement Warrants and the Pre-Funded Warrants should be equity classified in accordance with ASC 480 for the period ended March 31, 2020. The Company also determined that the Pre-Funded Warrants should be included in the determination of basic earnings per share in accordance with ASC 260, Earnings per Share.