Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 61,014	$ 66,260
Investments	47,437	100,218
Trade accounts receivable	3,222	1,860
Inventory	8,059	7,746
Prepaid expenses	955	980
Other current assets	1,165	576
Total current assets	121,852	177,640
Property and equipment, net	7,905	7,303
Right of use assets	3,917
Other non-current assets	750	322
Total assets	134,424	185,265
Current liabilities:
Accounts payable	2,351	1,322
Accrued liabilities	3,828	4,962
Accrued interest	1,262	1,262
Deferred revenue	271	217
Current operating lease liability	450
Total current liabilities	8,162	7,763
Non-current operating lease liability	3,579
Other non-current liabilities	19	53
Convertible notes	130,043	120,074
Total liabilities	141,803	127,890
Commitments and contingencies
Stockholders' equity (deficit):
Preferred shares	0	0
Common stock, $0.001 par value	55	54
Contributed capital	452,344	432,885
Treasury stock	(45,067)	(45,067)
Accumulated deficit	(414,653)	(330,348)
Accumulated other comprehensive loss	(58)	(149)
Total stockholders' equity (deficit)	(7,379)	57,375
Total liabilities and stockholders' equity (deficit)	$ 134,424	$ 185,265