Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net (loss) income	$ (1,339,000)	$ 2,314,000
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Bargain purchase gain		(6,988,000)
Depreciation and amortization	1,100,000	511,000
Stock-based compensation	164,000	86,000
Loss on revaluation of financial instruments		3,000
Non-cash interest expense	35,000	323,000
Amortization of note discount		18,000
Non-cash interest expense related to sale of future royalties	544,000	298,000
Non-cash revenue related to sale of future royalties	(1,384,000)
Change in operating assets and liabilities:
Accounts receivable	(3,788,000)	1,947,000
Prepaid expenses and other assets	100,000	(469,000)
Accounts payable	(184,000)	(3,097,000)
Accrued liabilities	99,000	(5,536,000)
Net cash used in operating activities	(4,653,000)	(10,590,000)
Cash flows from investing activities:
Purchase of property and equipment	(552,000)	(140,000)
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	(552,000)	26,779,000
Cash flows from financing activities:
Net proceeds from issuance of common stock in registered direct offering	2,540,000
Repayment of principal on secured promissory note payable to Oxford Finance	(417,000)	(278,000)
Proceeds from issuance of common stock upon exercise of stock options		13,000
Net cash provided by (used in) financing activities	2,123,000	(265,000)
Net (decrease) increase in cash and cash equivalents	(3,082,000)	15,924,000
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	8,424,000	17,495,000
Supplemental disclosure of cash flow information:
Interest paid	72,000	95,000
Supplemental disclosure of non-cash financing activity:
Issuance of warrants to placement agent's representatives	100,000
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	$ 123,000	$ 72,000