Summary of Significant Accounting Policies - (Tables)

6 Months Ended

Jun. 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 six month periods ended June 30, 2020 and 2019:

	Three Months Ended June 30,		Six Months Ended June 30,
	2020	2019	2020	2019
Expected common stock price volatility	118%	88%	117%	87%
Risk-free interest rate	0.26%-0.36%	2.15%-2.31%	0.26%-1.34%	2.15%-2.54%
Expected term of options (years)	4.5	5.3	4.5	5.6
Expected dividend yield	—	—	—	—