Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 20,007,659	$ 27,666,055
Marketable investment securities	24,375,168	0
Accrued interest income	144,536	0
Prepaid and other current assets	350,160	229,912
Total current assets	44,877,523	27,895,967
Property and equipment, net of accumulated depreciation of $1,060,750 and $1,034,029, respectively	75,750	73,782
Long-term marketable investment securities	400,252	0
Other assets	23,753	23,753
Total assets	45,377,278	27,993,502
Current liabilities:
Accounts payable	507,067	306,276
Accrued expenses	2,884,794	1,327,256
Total current liabilities	3,391,861	1,633,532
Total liabilities	$ 3,391,861	$ 1,633,532
Commitments and contingencies (notes 7 and 10)
Stockholders' equity:
Preferred stock, par value $0.0001 per share, 10,000,000 shares authorized; zero issued and outstanding	$ 0	$ 0
Common stock, par value $0.0001 per share, 100,000,000 shares authorized; 18,250,456 and 12,800,382 issued and 18,244,746 and 12,794,672 outstanding	1,825	1,280
Additional paid-in capital	128,502,659	94,636,479
Treasury stock at cost, 5,710 shares	(40,712)	(40,712)
Accumulated other comprehensive loss	(32,900)	0
Accumulated deficit	(86,445,455)	(68,237,077)
Total stockholders' equity	41,985,417	26,359,970
Total liabilities and stockholders' equity	$ 45,377,278	$ 27,993,502

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).

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Balance Type:	credit
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- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).