Summary of Significant Accounting Policies - (Tables)

3 Months Ended

Mar. 31, 2021

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 month periods ended March 31, 2021 and 2020:

	Three Months Ended March 31,
	2021	2020
Expected common stock price volatility	113%	115%
Risk-free interest rate	0.39%-0.96%	0.87%-1.34%
Expected term of options (years)	5.3	4.7
Expected dividend yield	—	—