Warrants

12 Months Ended

Dec. 31, 2023

Text Block [Abstract]

Warrants

Note 6. Warrants

The Company has issued multiple warrant series, of which the 2018 PIPE Warrants were determined to be liabilities pursuant to the guidance established by ASC 815 Derivatives and Hedging.

Warrants Issued as Part of the Units in the 2018 PIPE Offering

The 2018 PIPE Warrants were issued on December 19, 2018 in the 2018 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2018 PIPE Offering, and prior to their expiration on December 21, 2023, entitled the holders to purchase 34,241 shares of the Company’s common stock at an exercise price equal to $30.00 per share, subject to adjustments.

In the event of a change of control of the Company, the holders of unexercised warrants had the option to present their unexercised warrants to the Company, or its successor, to be purchased by the Company, or its successor, in an amount equal to the per share value determined by the Black-Scholes methodology.

Since the Company may have been obligated to settle the 2018 PIPE Warrants in cash, the Company classified the 2018 PIPE Warrants as long-term liabilities at their fair value and re-measured the warrants at each balance sheet date until they were exercised or expire. Any change in the fair value is recognized as Other income (expense) in the Company’s consolidated statements of operations.

There were no 2018 PIPE Warrants outstanding at December 31, 2023 as the warrants were either exercised or expired, and the Company estimated the fair value of the liability for the 2018 PIPE Warrants at approximately $1 thousand at December 31, 2022. During 2023, 21,789 2018 PIPE Warrants were exercised for net proceeds of $0.2 million, and the Company issued 9,683 shares of common stock. The remaining 12,452 2018 PIPE Warrants expired. The increase of $0.2 million and the decrease of $30 thousand in the fair value of the liability for the 2018 PIPE Warrants during the years ended December 31, 2023 and 2022, respectively, was recorded as Other income in the consolidated statements of operations.

The Company has calculated the fair value of the 2018 PIPE Warrants using a Black-Scholes option-pricing model. The following summarizes certain key assumptions used in estimating the fair values:

	December 31, 2022
Volatility		117	%
Contractual term (years)		1.0
Expected dividend yield		—	%
Risk-free rate		4.74	%

The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. These assumptions include the following estimates:

•Volatility: The Company calculated the estimated volatility rate based on its historical volatility of the warrants.

•Contractual term: The expected life of the warrants, which is based on the contractual term of the warrants.

•Expected dividend yield: The Company has never declared or paid any cash dividends and does not currently plan to pay cash dividends in the foreseeable future. Consequently, the Company used an expected dividend yield of zero.

•Risk-free rate: The risk-free interest rate is based on the U.S. Treasury rate for similar periods as the expected life of the warrants.