Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the nine months ended September 30, 2020 is as follows:

						Weighted
						Average
				Weighted		Remaining
	Number of			Average Exercise		Contractual
	Shares			Price Per Share		Term in Years
Outstanding at December 31, 2019		273,406		$	36.14		9.25
Granted		13,870		$	5.23
Exercised		—			—
Cancelled/forfeited/expired		(32,920	)	$	16.09
Outstanding at September 30, 2020		254,356		$	37.04		8.50
Vested and unvested expected to vest at September 30, 2020		250,368		$	37.48		8.50

Assumptions Used for Determining Fair Value of Stock Options Under Black-Scholes Pricing Model

The assumptions used in the Black-Scholes pricing model for stock options granted during the nine months ended September 30, 2020 were as follows:

Stock and exercise prices	$2.70 - $7.10
Expected dividend yield		0.00%
Discount rate-bond equivalent yield	0.38% – 1.37%
Expected life (in years)	5.00 – 5.96
Expected volatility	146.1% - 171.1%

Summary of RSU Activity

A summary of RSU activity for the nine months ended September 30, 2020 is as follows:

			Weighted
	Number of		Average Grant
	Shares		Date Fair Value
Outstanding at December 31, 2019		36	$	4,158
Granted		—		—
Vested and issued		—		—
Forfeited		—		—
Outstanding at September 30, 2020		36	$	4,158
Vested and unvested expected to vest at September 30, 2020		36	$	4,158

Effects of Stock-Based Compensation Related to Equity Awards to Employees and Nonemployees on Condensed Statement of Operations and Comprehensive Loss

The following table presents the effects of stock-based compensation related to equity awards to employees and nonemployees on the unaudited condensed statements of operations and comprehensive loss during the periods presented:

	For the three months ended				For the nine months ended
	September 30,				September 30,
	2019		2020		2019		2020
Stock Options
Cost of revenues	$	29,405	$	25,352	$	54,625	$	78,917
Research and development expenses		37,626		25,397		102,742		78,914
General and administrative expenses		168,484		92,472		361,102		290,231
Sales and marketing expenses		62,154		23,509		106,300		55,868
Total expenses related to stock options	$	297,669	$	166,730	$	624,769	$	503,930