Consolidated Balance Sheets - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 240,429,839	$ 62,251,860
Prepaid expenses and other current assets	4,750,469	909,629
Total current assets	245,180,308	63,161,489
Property and equipment, net	24,200,582	235,590
Other long-term assets	1,194,541	1,687,212
Total assets	270,575,431	65,084,291
Current liabilities:
Accounts payable	3,197,274	359,787
Accrued expenses	16,794,003	2,437,017
Accrued indemnification obligation	4,452,500	4,080,500
Total current liabilities	24,443,777	6,877,304
Total liabilities	24,443,777	6,877,304
Redeemable common stock; par value $0.0001 per share, no shares issued and outstanding at December 31, 2016; 456,043 shares issued and outstanding at December 31, 2015		1,032,909
Stockholders' equity (deficit):
Common stock; par value $0.0001 per share, 100,000,000 shares authorized, 27,700,054 shares issued and outstanding at December 31, 2016; 22,080,000 shares authorized, 6,817,093 shares issued and outstanding at December 31, 2015	2,770	682
Additional paid-in capital	387,691,208	115,723,046
Accumulated deficit	(141,562,324)	(58,550,520)
Total stockholder's equity (deficit)	246,131,654	57,174,078
Total liabilities, redeemable common stock and stockholders' equity (deficit)	$ 270,575,431	65,084,291
Class D Preferred Stock
Stockholders' equity (deficit):
Preferred stock		309
Total stockholder's equity (deficit)		309
Class C Preferred Stock
Stockholders' equity (deficit):
Preferred stock		237
Total stockholder's equity (deficit)		237
Class B-1 Preferred Stock
Stockholders' equity (deficit):
Preferred stock		324
Total stockholder's equity (deficit)		$ 324