Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 10,701	$ 17,278
Accounts receivable	2,278	1,298
Inventory	4,272	4,348
Prepaid expenses and other	365	330
Total current assets	17,616	23,254
Property and equipment, net	716	758
Intangible assets, net	2,987	3,215
Deferred offering costs	1,731
Total assets	23,050	27,227
Current liabilities:
Accounts payable	1,701	3,421
Accrued expenses	3,600	5,153
Other current liabilities	1,008	985
Total current liabilities	6,309	9,559
Long-term debt with related party	30,108	29,733
Preferred stock warrant liability	1,644	1,640
Other long-term liabilities	5	5
Total liabilities	38,066	40,937
Redeemable convertible preferred stock	145,384	124,150
Stockholders' deficit:
Accumulated other comprehensive loss	(2)
Accumulated deficit	(160,398)	(137,860)
Total stockholders' deficit	(160,400)	(137,860)
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	23,050	27,227
Series A Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock	34,458	33,112
Series B Redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock	$ 110,926	$ 91,038