Summary of Significant Accounting Policies - (Tables)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Schedule of weighted-average assumptions used to estimate grant date fair value of stock options

The weighted-average assumptions used to estimate grant date fair value of stock options using the Black-Scholes option pricing model were as follows for the three and nine month periods ended September 30, 2020 and 2019:

	Three Months Ended September 30,		Nine Months Ended September 30,
	2020	2019	2020	2019
Expected common stock price volatility	117%	89%	117%	88%
Risk-free interest rate	0.22%-0.26%	1.38%-1.84%	0.22%-1.34%	1.38%-2.54%
Expected term of options (years)	4.8	6.1	4.6	5.7
Expected dividend yield	—	—	—	—