Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (18,645,000)	$ (18,007,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Bargain purchase gain		(6,760,000)	[1]
Depreciation and amortization	3,596,000	3,203,000
(Gain) loss on sale of equipment	(1,000)	11,000
Impairment of intangible assets		1,600,000
Impairment of property and equipment and right-of-use assets	1,272,000	106,000
Stock-based compensation	627,000	539,000
Loss on revaluation of financial instruments		3,000
Non-cash interest expense	88,000	448,000
Amortization of note discount		18,000
Loss on debt extinguishment	100,000
Non-cash interest expense related to the sale of future royalties	2,073,000	1,859,000
Non-cash revenue related to the sale of future royalties	(3,482,000)	(18,000)
Change in operating assets and liabilities:
Accounts receivable	(1,823,000)	13,500,000
Prepaid expenses and other assets	855,000	(873,000)
Accounts payable	(62,000)	(3,784,000)
Accrued liabilities	2,312,000	(6,393,000)
Net cash used in operating activities	(13,090,000)	(14,548,000)
Cash flows from investing activities:
Purchase of property and equipment	(850,000)	(707,000)
Proceeds from sale of equipment
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	(850,000)	26,212,000
Cash flows from financing activities:
Net proceeds from issuance of common stock in registered direct offering	2,540,000
Exercise of pre-funded warrants	1,226,000
Exercise of common stock warrants	180,000
Repayment of principal on secured promissory note payable to Oxford Finance	(3,799,000)	(1,528,000)
Repayment of short-term note		(214,000)
Proceeds from issuance of common stock upon exercise of stock options		13,000
Net cash provided by (used in) financing activities	15,960,000	(1,729,000)
Net increase in cash and cash equivalents	2,020,000	9,935,000
Cash and cash equivalents at beginning of the period	11,506,000	1,571,000
Cash and cash equivalents at end of the period	13,526,000	11,506,000
Supplemental disclosure of cash flow information:
Interest paid	227,000	356,000
Supplemental disclosure of non-cash investing and financing activity:
Issuance of warrants to placement agents’ designees	100,000
Issuance of warrants to underwriters’ designees	830,000
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
Operating lease liabilities arising from obtaining right-of-use assets	1,929,000
Acquisition of property and equipment included in accounts payable	4,000	52,000
Proceeds due for sale of property and equipment included in prepaid expenses and other current assets	3,000
The April 2019 Offering [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock, pre-funded warrants and common warrants in underwritten offering	8,074,000
The September 2019 Offering [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock, pre-funded warrants and common warrants in underwritten offering	$ 7,739,000

[1] The bargain purchase gain represents the excess of the fair value of tangible and identified intangible assets acquired, less liabilities assumed, over the purchase price.