Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2020

Equity [Abstract]

Summary of Estimated Fair Value of Stock Option Award

During the three months ended March 31, 2020, the Company granted stock options to purchase 875,000 shares of the Company’s common stock. Of such options, 50% do not begin vesting until the date, if any, that FDA approves 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, 2020 and 2019:

	Three Months Ended March 31,
	2020	2019
Common Stock Options
Risk free interest rate	0.96%	2.55%
Expected option term	6.0 years	6.0 years
Expected volatility of common stock	99.73%	90.34%
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 and 2019:

	Three Months Ended March 31,
	2020	2019
Employee Stock Purchase Plan
Risk free interest rate	1.11%	2.52%
Expected term	6.0 months	6.0 months
Expected volatility of common stock	69.72%	130.36%
Expected dividend yield	0.0%	0.0%

Summary of Recognized Non-Cash Stock-Based Compensation Expense

The Company recognized non-cash stock-based compensation expense to employees and directors in its research and development and its general and administrative functions during the three months ended March 31, 2020 and 2019 as follows:

	Three Months Ended March 31,
	2020		2019
Research and development	$	120,562	$	152,174
General and administrative		189,600		226,785
Total stock-based compensation expense	$	310,162	$	378,959