WARRANTS

From time to time, we have issued warrants to purchase shares of common stock. These warrants have been issued in connection with the financing transactions and consulting services. Our warrants are subject to standard anti-dilution provisions applicable to shares of our common stock.

A roll-forward of warrant share activity from January 1, 2020 to June 30, 2020 is shown in the following table:



	Exercise Price	Expiration Date	Issued and Outstanding Warrants as of January 1, 2020	Warrants Exercised/ Expired			Issued and Outstanding Warrants as of June 30, 2020
Consulting Warrants	$0.01	6/17/2020	6,667	(6,667	)	(1)	—
Financing Warrants	$3.35	6/17/2020	62,530	(62,530	)	(2)	—
Private Placement Warrants - September 2017	$4.85	9/28/2020	1,966,319	—			1,966,319
Placement Agent Warrants	$4.85	9/28/2020	98,846	—			98,846
			2,134,362	(69,197	)		2,065,165

(1) During the six months ended June 30, 2020, there were 6,667 warrants that were exercised through a cashless exercise which netted 6,640 shares being issued.

(2) During the six months ended June 30, 2020, there were 62,530 warrants that expired.

A roll-forward of warrant share activity from January 1, 2019 to June 30, 2019 is shown in the following table:



	Issued and Outstanding Warrants as of January 1, 2019	Warrants Exercised/ Expired			Issued and Outstanding Warrants as of June 30, 2019
Consulting Warrants	6,667	—			6,667
Financing Warrants	62,530	—			62,530
Underwriting Warrants	310,500	(310,500	)	(1)	—
Private Placement Warrants - 2016	818,063	(818,063	)	(2)	—
Underwriting Warrants - Public Offering 2016	122,175	—			122,175
Private Placement Warrants - September 2017	1,966,319	—			1,966,319
Placement Agent Warrants	98,846	—			98,846
	3,385,100	(1,128,563	)		2,256,537

(1) During the six months ended June 30, 2019, there were 310,500 warrants that expired.

(2) During the six months ended June 30, 2019, there were 485,000 warrants exercised for cash, 44,928 warrants that were exercised through a cashless exercise which netted 1,809 shares being issued and 288,135 warrants that expired.