Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid In Capital	Accumulated Deficit
Beginning Balance (in shares) at Dec. 31, 2017		2,535,766
Beginning Balance at Dec. 31, 2017	$ 13,000	$ 2	$ 66,223	$ (53,225)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		0
Exercise of stock options	0	$ 0	0
Exercise of warrants (in shares)		2,400
Exercise of warrants	24		24
Issuance of common stock, net of issuance costs (in shares)		48,634
Issuance of common stock, net of issuance costs	642	$ 1	641
Stock based compensation from issuance of stock options	1,609		1,609
Net loss	(9,343)			(9,343)
Ending Balance (in shares) at Mar. 31, 2018		2,586,800
Ending Balance at Mar. 31, 2018	5,932	$ 3	68,497	(62,568)
Beginning Balance (in shares) at Dec. 31, 2017		2,535,766
Beginning Balance at Dec. 31, 2017	13,000	$ 2	66,223	(53,225)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(10,740)
Ending Balance (in shares) at Jun. 30, 2018		2,711,645
Ending Balance at Jun. 30, 2018	8,376	$ 3	72,338	(63,965)
Beginning Balance (in shares) at Mar. 31, 2018		2,586,800
Beginning Balance at Mar. 31, 2018	5,932	$ 3	68,497	(62,568)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		7,063
Exercise of stock options	0	$ 0	0
Stock issued for services (in shares)		38,166
Stock issued for services	782		782
Issuance of common stock, net of issuance costs (in shares)		79,616
Issuance of common stock, net of issuance costs	1,527	$ 0	1,527
Stock based compensation from issuance of stock options	1,532		1,532
Net loss	(1,397)			(1,397)
Ending Balance (in shares) at Jun. 30, 2018		2,711,645
Ending Balance at Jun. 30, 2018	8,376	$ 3	72,338	(63,965)
Beginning Balance (in shares) at Dec. 31, 2018		3,845,361
Beginning Balance at Dec. 31, 2018	16,859	$ 4	91,276	(74,421)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		80,000
Exercise of stock options	601		601
Stock based compensation from issuance of stock options	1,066		1,066
Net loss	(1,736)			(1,736)
Ending Balance (in shares) at Mar. 31, 2019		3,925,361
Ending Balance at Mar. 31, 2019	16,790	$ 4	92,943	(76,157)
Beginning Balance (in shares) at Dec. 31, 2018		3,845,361
Beginning Balance at Dec. 31, 2018	16,859	$ 4	91,276	(74,421)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs (in shares)		180,139
Net loss	(158)
Ending Balance (in shares) at Jun. 30, 2019		4,025,500
Ending Balance at Jun. 30, 2019	20,063	$ 4	94,638	(74,579)
Beginning Balance (in shares) at Mar. 31, 2019		3,925,361
Beginning Balance at Mar. 31, 2019	16,790	$ 4	92,943	(76,157)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		100,139
Exercise of stock options	834	$ 0	834
Stock based compensation from issuance of stock options	861		861
Net loss	1,578			1,578
Ending Balance (in shares) at Jun. 30, 2019		4,025,500
Ending Balance at Jun. 30, 2019	$ 20,063	$ 4	$ 94,638	$ (74,579)