Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net loss	$ (6,976,000)	$ (6,557,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Bargain purchase gain		(6,660,000)
Depreciation and amortization	2,097,000	1,437,000
Impairment of intangible assets		1,600,000
Stock-based compensation	344,000	204,000
Loss on revaluation of financial instruments		3,000
Non-cash interest expense	64,000	366,000
Amortization of note discount		18,000
Non-cash interest expense related to sale of future royalties	1,060,000	766,000
Non-cash revenue related to sale of future royalties	(3,132,000)
Change in operating assets and liabilities:
Accounts receivable	1,761,000	14,735,000
Prepaid expenses and other assets	530,000	(448,000)
Accounts payable	(347,000)	(3,259,000)
Accrued liabilities	(371,000)	(5,693,000)
Net cash used in operating activities	(4,970,000)	(3,488,000)
Cash flows from investing activities:
Purchase of property and equipment	(711,000)	(339,000)
Cash acquired in reverse merger		25,525,000
Cash paid for fractional shares in merger		(21,000)
Purchases of short-term investments		(573,000)
Proceeds from maturities of short-term investments		1,988,000
Net cash (used in) provided by investing activities	(711,000)	26,580,000
Cash flows from financing activities:
Net proceeds from issuance of common stock in registered direct offering	2,540,000
Net proceeds from issuance of common stock, pre-funded warrants and common warrants in underwritten offering	8,074,000
Repayment of principal on secured promissory note payable to Oxford Finance	(833,000)	(694,000)
Repayment of short-term note		(61,000)
Proceeds from issuance of common stock upon exercise of pre-funded warrants	652,000
Proceeds from issuance of common stock upon exercise of stock options		13,000
Net cash provided by (used in) financing activities	10,433,000	(742,000)
Net increase in cash and cash equivalents	4,752,000	22,350,000
Cash, cash equivalents and restricted cash at beginning of the period	11,506,000	1,571,000
Cash, cash equivalents and restricted cash at end of the period	16,258,000	23,921,000
Supplemental disclosure of cash flow information:
Interest paid	136,000	189,000
Supplemental disclosure of non-cash investing and financing activity:
Issuance of warrants to placement agents’ designees	100,000
Issuance of warrants to underwriters’ designees	333,000
Issuance of common stock upon reverse merger, net of cash paid for partial shares		31,768,000
Conversion of convertible promissory notes, related parties into common stock upon reverse merger		35,577,000
Reclassification of convertible preferred stock warrant liability to equity		70,000
Acquisition of property and equipment included in accounts payable	$ 47,000	$ 14,000