CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (4,143)	$ (4,537)
Adjustment to reconcile net loss to net cash used in operating activities:
Non-cash stock-based compensation	145	185
Change in fair value of common stock warrants	(35)	(195)
Change in fair value of contingent consideration	138	387
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(1,350)	(302)
Accounts payable	(1,303)	883
Accrued expenses and other current liabilities	(283)	(1,412)
Net cash used in operating activities	(6,831)	(4,991)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of offering costs	5,988	0
Collection of stock subscription receivable	308	0
Net proceeds from exercise of warrants	4	2,230
Net cash provided by financing activities	6,300	2,230
Net decrease in cash, cash equivalents, restricted cash, and restricted cash equivalents	(531)	(2,761)
Cash, cash equivalents, restricted cash, and restricted cash equivalents at the beginning of period	7,377	5,451
Cash, cash equivalents, restricted cash, and restricted cash equivalents at the end of period	6,846	2,690
Supplemental disclosure of cash flow information:
Cash received during the periods for interest	24	14
Supplemental disclosure of non-cash investing and financing activities:
Operating right of use asset and current and non-current liability	123	0
Impact of anti-dilution protection on liability-classified warrants	0	173
Offering expenses in accounts payable and accrued expenses and other current liabilities	$ 25	$ 0