Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 46,407	$ 12,620
Restricted cash, current portion	4,597	59
Short-term investments	107,461	106,247
Accounts receivable, net of allowance of $1,788 in 2018 and $2,000 in 2017	62,223	44,089
Inventory	13,633	8,998
Prepaid expenses and other current assets	6,197	8,612
Total current assets	240,518	180,625
Property and equipment, net	24,336	29,667
Restricted cash, long term portion		342
Other assets	3,317	3,979
Total assets	268,171	214,613
Current liabilities:
Accounts payable	14,587	8,529
Accrued compensation	12,668	9,599
Other accrued liabilities	32,442	33,257
Deferred revenue, current portion	4,131	1,420
Short-term debt financing	50,153	50,112
Warrants		2,644
Total current liabilities	113,981	105,561
Long-term debt financing	73,357	73,065
Deferred rent, net of current portion	8,613	9,241
Deferred revenue, long-term portion	40,058
Other long-term liabilities		1,329
Total liabilities	236,009	189,196
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $0.0001 par value: 50,000 shares authorized; no shares issued and outstanding at December 31, 2018 and 2017, respectively
Common stock, $0.0001 par value: 750,000 shares authorized at December 31, 2018 and 2017, respectively; 62,083 and 54,040 shares issued and outstanding at December 31, 2018 and 2017, respectively	7	6
Additional paid in capital	607,236	472,552
Accumulated deficit	(574,529)	(446,375)
Accumulated other comprehensive loss	(552)	(766)
Total stockholders' equity	32,162	25,417
Total liabilities and stockholders' equity	$ 268,171	$ 214,613