Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 51,441	$ 118,564
Restricted cash	555	55
Marketable securities	179,730	134,714
Accounts receivable, net	10,957	4,441
Inventory	6,220	4,366
Prepaid expenses	6,527	5,175
Other current assets	1,467	2,191
Total current assets	256,897	269,506
Investments	86,763	176,978
Property and equipment, net	5,210	6,195
Intangible assets	7,781	8,180
Other assets	633	799
Total assets	357,284	461,658
Current liabilities:
Accounts payable	2,532	3,915
Accrued expenses and other current liabilities	45,177	49,512
Total current liabilities	47,709	53,427
Other non-current liabilities	142	189
Notes payable	172,674	166,006
Total liabilities	220,525	219,622
Commitments and contingencies
Stockholders’ equity:
Common stock, $.0001 par value; 200,000,000 shares authorized, 45,476,455 shares and 44,616,586 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	5	4
Additional paid-in-capital	1,150,765	1,124,630
Accumulated other comprehensive loss	(1,290)	(314)
Accumulated deficit	(1,012,721)	(882,284)
Total stockholders’ equity	136,759	242,036
Total liabilities and stockholders’ equity	$ 357,284	$ 461,658