Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 332,828,289	$ 61,325,044
Investment securities, available-for-sale	177,903,693	68,320,672
Accounts receivable		51,603
Prepaid expenses and other current assets	1,532,908	1,288,953
Total current assets	512,264,890	130,986,272
Property and equipment, net	785,544	54,553
Other assets	71,875	70,944
Total assets	513,122,309	131,111,769
Current liabilities:
Accounts payable	705,043	2,052,765
Accrued and other current liabilities	8,575,333	7,529,241
Accrued employee benefits	1,106,620	975,058
Total current liabilities	10,386,996	10,557,064
Long-term deferred rent	881,143
Total liabilities	11,268,139	10,557,064
Stockholders' equity:
Common stock, $.0001 par value: 100,000,000 shares authorized; 43,009,886 and 29,499,059 shares issued and outstanding at September 30, 2015 and December 31, 2014, respectively	4,301	2,950
Additional paid-in capital	666,083,825	208,912,345
Accumulated deficit	(164,214,582)	(88,255,957)
Accumulated comprehensive loss	(19,374)	(104,633)
Total stockholders' equity	501,854,170	120,554,705
Total liabilities and stockholders' equity	$ 513,122,309	$ 131,111,769

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.