Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 20,659	$ 16,380
Investments	0	7,245
Accounts receivable, net	11,249	13,244
Royalty receivable	168	145
Inventories	10,638	9,534
Prepaid expenses and other current assets	1,531	1,408
Total current assets	44,245	47,956
Property and equipment, net	13,649	14,439
Operating lease right-of-use assets	6,415
Other Assets
Restricted cash	462	462
Intangible assets, net	49	109
Other long-term assets	218	17
Total assets	65,038	62,983
Current liabilities
Accounts payable	4,182	3,445
Accrued expenses	7,100	7,930
Operating lease liabilities	1,440
Total current liabilities	12,722	11,375
Other long-term liabilities	0	616
Long-term debt, less debt issuance costs	19,323	14,792
Operating lease liabilities	5,692
Total liabilities	37,737	26,783
Commitments and contingencies	0	0
Stockholders’ equity
Preferred stock, $0.00001 par value: Authorized: 5,000,000 shares authorized as of June 30, 2019 and December 31, 2018; no shares issued and outstanding as of June 30, 2019 and December 31, 2018	0	0
Common stock, $0.00001 par value: Authorized: 200,000,000 shares authorized as of June 30, 2019 and December 31, 2018; 68,689,192 and 65,290,879 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	1	1
Additional paid-in capital	518,563	513,336
Accumulated deficit	(490,011)	(475,667)
Accumulated other comprehensive loss	(1,252)	(1,470)
Total stockholders’ equity	27,301	36,200
Total liabilities and stockholders’ equity	$ 65,038	$ 62,983