Warrants (Tables)

12 Months Ended

Dec. 31, 2019

Warrants [Abstract]

Summary of Warrants Issued and Warrants Outstanding

	Issued		Outstanding		Exercise Price		Expire
2015 Warrant Issuance		383,500		383,500		2.05		Jun 2021
2016 Warrant Issuance		2,947,949		2,947,949		2.60		Feb 2023
2017 Warrant Issuance  (1)(2)		100,000		100,000		2.25		Mar 2022
2017 Warrant Issuance  (1)		1,650,000		1,650,000		2.45		Nov 2022
2018 Warrant Issuance  (1)		4,004,324		3,974,324		1.55		Jul 2023
2019 Warrant Issuance		240,000		240,000		0.55		Apr 2024
2019 Warrant Issuance  (3)		4,000,000		4,000,000		0.49		Oct 2024
2019 Warrant Issuance  (4)		6,000,000		6,000,000		0.78		Oct 2024

(1) Warrants are subject to liability accounting.

(2) Issued in conjunction with an unsecured line of credit as described in Note 9: Debt / Line of Credit.

(3) Immediately exercisable pre-funded warrants at an exercise price of $0.01 per share.

(4) Private Placement unregistered warrants exercisable six months following issuance.

Fair Value of Warrants

	2019		2018
2018 January and February Issuance
Fair Value at December 31,	$	22	$	1,342
2017 May issuance
Fair Value at December 31,		1		155
	$	23	$	1,497
	Twelve Months Ended
	December 31,
Change in Fair Value of common stock warrant liability (1)	$	1,474	$	2,194

(1) The combined changes in fair value is reflected as income from change in the fair market value of common stock warrant liability.