Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 16,557	$ 28,947
Restricted cash, current portion	1,274	901
Short-term investments	198,647	201,586
Accounts receivable, net of allowance of $1,213 in 2016 and $971 in 2015	6,171	5,862
Inventory	8,893	8,093
Prepaid expenses and other current assets	5,633	5,337
Total current assets	237,175	250,726
Property and equipment, net	19,096	12,710
Restricted cash, long term portion	342	683
Other assets	4,654	1,121
Total assets	261,267	265,240
Current liabilities:
Accounts payable	9,194	7,332
Accrued compensation	9,095	8,552
Other accrued liabilities	23,586	18,708
Deferred revenue	331	144
Short-term debt financing	49,327	42,090
Warrants	3,955	3,649
Total current liabilities	95,488	80,475
Deferred rent	1,964
Total liabilities	97,452	80,475
Commitments and contingencies (Note 6)
Stockholders’ equity:
Common stock	6	5
Additional paid in capital	444,790	436,259
Accumulated deficit	(281,924)	(250,083)
Accumulated other comprehensive income (loss)	943	(1,416)
Total stockholders’ equity	163,815	184,765
Total liabilities and stockholders’ equity	$ 261,267	$ 265,240