v3.21.1
Stockholders’ Equity and Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2021
Share-based Payment Arrangement [Abstract]  
Schedule of Warrant Activity
A summary of the Company’s warrant activity during the three months ended March 31, 2021 was as follows:
Shares of Stock under WarrantsWeighted-
Average
Exercise
Price
Weighted-
Average
Remaining
Contractual
Term
Aggregate
Intrinsic
Value
Outstanding at January 1, 202115,174,000 $2.34 3.76$26,841,000 
Granted— 
Exercised(10,739,000)0.89 57,912,000 
Canceled(24,000)
Outstanding at March 31, 2021
4,411,000 $5.89 2.50$2,911,000 
Summary of Stock Option Activity
A summary of the Company’s stock option activity during the three months ended March 31, 2021 was as follows:   
Shares of Stock under Stock OptionsWeighted-
Average
Exercise
Price
Weighted-
Average
Remaining
Contractual
Term
Aggregate
Intrinsic
Value
Outstanding at January 1, 20215,290,000 $1.91 8.7$10,178,000 
Granted138,000 10.83 
Exercised(102,000)3.28 $1,153,000 
Canceled(200,000)0.97 
Outstanding at March 31, 2021
5,126,000 $2.16 8.66$31,554,000 
Vested and exercisable at March 31, 2021
1,704,000 $3.62 8.02$8,403,000 
Summary of Recognized Stock-Based Compensation Expense
The Company recognized stock-based compensation expense for the periods presented as follows: 
 Three Months Ended
March 31,
20212020
Research and development$81,000 $67,000 
General and administrative290,000 261,000 
Total stock-based compensation expense$371,000 $328,000 
Schedule of Weighted-Average Assumptions in Black -Scholes Option Pricing Model
The weighted-average assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants during the periods presented were as follows:
Three Months Ended
March 31,
20212020
Risk-free interest rate0.7 %1.4 %
Expected volatility79.3 %70.0 %
Expected term (in years)6.16.0
Expected dividend yield0.0 %0.0 %