Warrant Liabilities (Tables)

9 Months Ended

Sep. 30, 2020

Series C Warrant [Member]

Fair Value of Convertible Preferred Stock Warrant Liability

The Company used the following inputs.

	December 31, 2019
Volatility		90	%
Contractual term (years)		0.17
Expected dividend yield		—	%
Risk-free rate		1.52	%

2017 PIPE Warrant Liability [Member]

Fair Value of Convertible Preferred Stock Warrant Liability

The following summarizes certain key assumptions used in estimating the fair values.

	September 30, 2020			December 31, 2019
Volatility		123	%		99	%
Contractual term (years)		0.2			1.0
Expected dividend yield		—	%		—	%
Risk-free rate		0.10	%		1.60	%

2018 PIPE Warrant Liability [Member]

Fair Value of Convertible Preferred Stock Warrant Liability

The following summarizes certain key assumptions used in estimating the fair values.

	September 30, 2020			December 31, 2019
Volatility		100	%		99	%
Contractual term (years)		3.2			4.0
Expected dividend yield		—	%		—	%
Risk-free rate		0.17	%		1.56	%