Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 118,564	$ 258,567
Restricted cash	55	47
Marketable securities	134,714	73,880
Accounts receivable, net	4,441	0
Inventory	4,366	0
Prepaid expenses	5,175	1,486
Other current assets	2,191	829
Total current assets	269,506	334,809
Investments	176,978	0
Property and equipment, net	6,195	4,922
Intangible assets	8,180	0
Other assets	799	551
Total assets	461,658	340,282
Current liabilities:
Accounts payable	3,915	6,128
Accrued expenses and other current liabilities	49,512	26,597
Total current liabilities	53,427	32,725
Other non-current liabilities	189	379
Notes payable	166,006	0
Total liabilities	219,622	33,104
Commitments and contingencies
Stockholders' equity:
Common stock, $.0001 par value; 200,000,000 shares authorized, 44,616,586 shares and 43,141,134 shares issued and outstanding at December 31, 2017 and 2016, respectively	4	4
Additional paid-in-capital	1,124,630	935,671
Accumulated other comprehensive income (loss)	(314)	71
Accumulated deficit	(882,284)	(628,568)
Total stockholders' equity	242,036	307,178
Total liabilities and stockholders' equity	$ 461,658	$ 340,282