Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (15,893)	$ (13,701)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	206	393
Noncash loss on extinguishment of debt		513
Noncash interest expense	395	398
Amortization of intangible assets	228	709
Inventory excess and obsolescence charge	1,093	1,550
Change in fair value of warrants	4	(191)
Stock-based compensation expense	183	169
Changes in operating assets and liabilities:
Accounts receivable	(983)	(475)
Inventory	(1,023)	(3,287)
Prepaid expenses and other assets	(35)	125
Accounts payable	(2,470)	1,178
Accrued expenses and other liabilities	(44)	(1,541)
Net cash used in operating activities	(18,339)	(14,160)
Cash flows from investing activities:
Payment for intangible asset	(2,500)
Purchase of property and equipment	(164)	(42)
Net cash used in investing activities	(2,664)	(42)
Cash flows from financing activities:
Proceeds from issuance of long-term debt and preferred stock warrants		8,000
Repayment of long-term debt		(5,000)
Borrowings under revolving credit facility		4,912
Repayments of revolving credit facility		(3,668)
Proceeds from issuance of Series B redeemable preferred stocks, net	14,415	1,349
Payment of deferred financing costs		(830)
Proceeds from exercise of stock options	12	6
Net cash provided by financing activities	14,427	4,769
Effect of exchange rate on cash	(1)
Net decrease in cash and cash equivalents	(6,577)	(9,433)
Cash and cash equivalents, beginning of period	17,278	11,346
Cash and cash equivalents, end of period	10,701	1,913
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	2,330	639
Cash paid on loss on extinguishment of debt		102
Supplemental disclosures of noncash investing and financing activities:
Fair value of warrants issued in connection with equity and debt financing		187
Accretion of redeemable convertible preferred stock to redemption value	(6,843)	(6,848)
Intangible assets in accrued expenses and other liabilities		4,000
Deferred Series B equity costs in accounts payable and accrued expenses	24
Deferred offering costs in accounts payable and accrued expenses	1,731
Issuance of common stock for early exercised stock options	$ 3	$ 3