Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (28,703)	$ (22,534)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	600	660
Change in right-of-use assets	145
Amortization of financing costs	13	9
Noncash interest expense	1,476	2,007
Share-based compensation expense	1,882	2,040
Obsolete inventory reserve	636	196
Change in fair value of derivative liabilities	0	4
Impairment of assets	0	20
Sales return provision	175	(158)
Changes in:
Accounts receivable	648	(870)
Inventories	(2,421)	870
Prepaid expense and other current assets	(269)	(538)
Other assets	(151)	(175)
Accounts payable	(176)	(1,473)
Accrued expense	2,199	166
Operating lease liabilities	(127)
Deferred rent liability	0	39
Net cash used in operating activities	(24,073)	(19,737)
Investing activities
Acquisition of property and equipment	(1,026)	(813)
Net cash used in investing activities	(1,026)	(813)
Financing activities
Repayment of finance lease	(59)	(46)
Proceeds from issuance of common stock and exercise of warrants, net of fees	4,659	27,542
Proceeds from issuance of common stock through ESPP	0	137
Net cash provided by financing activities	4,600	27,633
Net increase (decrease) in cash and cash equivalents	(20,499)	7,083
Cash and cash equivalents-beginning of period	27,259	33,044
Cash and cash equivalents-end of period	47,758	25,961
Supplemental disclosures of cash flow information
Right-of-use assets	2,592
Operating lease liability	2,700	0
Deferred rent	109
Cash interest payment on long-term debt	764	0
Commitment fee for Second Purchase Agreement	0	429
Deferred revenue reduction	0	1,638
Sales return reserve	0	778
Deferred cost of goods sold reduction (Note 3)	0	539
Accrued distribution fees and managed care costs	0	343
Noncash investing and financing
Capital lease obligation	0	315
Accrued offering costs	0	298
Property and equipment additions included in accounts payable	$ 190	$ 0