Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Summary of Estimated Fair Value of Stock Option Award

During the three months ended March 31, 2021 and 2020, the Company granted stock options to purchase 1,315,000 and 875,000 shares of the Company’s common stock, respectively. Of the options granted in 2020, 50% did not begin vesting until June 19, 2020, the date that FDA approved the Gimoti NDA. The estimated fair value of each stock option award granted was determined on the date of grant using the Black-Scholes option-pricing valuation model with the following weighted-average assumptions for option grants during the three months ended March 31, 2021 and 2020:

	Three Months Ended March 31,
	2021	2020
Common Stock Options
Risk free interest rate	0.57%	0.96%
Expected option term	6.0 years	6.0 years
Expected volatility of common stock	103.45%	99.73%
Expected dividend yield	0.0%	0.0%

Summary of Estimated Fair Value of Shares to be Acquired under Employee Stock Purchase Plan

The estimated fair value of the shares to be acquired under the ESPP was determined on the initiation date of each six-month purchase period using the Black-Scholes option-pricing valuation model with the following weighted-average assumptions for ESPP shares to be purchased during the three months ended March 31, 2020:

	Three Months Ended March 31,
	2020
Employee Stock Purchase Plan
Risk free interest rate	1.11%
Expected term	6.0 months
Expected volatility of common stock	69.72%
Expected dividend yield	0.0%

Summary of Recognized Stock-Based Compensation Expense

There were no employee withholdings to purchase shares during the six-month purchase period beginning March 1, 2021.

The Company recognized stock-based compensation expense to employees and directors in its research and development and its selling, general and administrative functions during the three months ended March 31, 2021 and 2020 as follows:

	Three Months Ended March 31,
	2021		2020
Research and development	$	68,380	$	120,562
Selling, general and administrative		492,968		189,600
Total stock-based compensation expense	$	561,348	$	310,162