Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 125,490	$ 200,990
Accounts receivable, net	10,746	2,310
Grants and other receivables	232	242
Inventory	4,404	7,132
Prepaid expenses and other current assets	3,230	2,183
Total current assets	144,102	212,857
Property and equipment, net	3,261	3,884
Other assets	2,014	248
Total assets	149,377	216,989
Current liabilities:
Accounts payable	5,112	7,116
Accrued expenses and other current liabilities	24,850	18,421
Deferred other income	0	160
Total current liabilities	29,962	25,697
Long-term debt, net	74,266	72,500
Other liabilities	631	181
Total liabilities	104,859	98,378
Stockholders' equity:
Common stock, $0.001 par value; 200,000,000 shares authorized at September 30, 2019 and December 31, 2018; 41,488,370 and 41,227,530 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	41	41
Additional paid-in capital	447,541	436,554
Accumulated deficit	(402,985)	(317,927)
Accumulated other comprehensive loss	(79)	(57)
Total stockholders' equity	44,518	118,611
Total liabilities and stockholders' equity	$ 149,377	$ 216,989