CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 40,255,062	$ 43,903,949
Prepaid expenses and deposits	1,716,092	1,526,442
Interest receivable	24,605	56,189
Total current assets	41,995,759	45,486,580
Non-current assets:
Property, plant and equipment, net	482,084	417,528
Right-of-use assets, net	407,813	455,174
Total non-current assets	889,897	872,702
Total assets	42,885,656	46,359,282
Current liabilities:
Accounts payable and accrued liabilities	2,955,293	1,757,680
Lease liability	209,081	204,132
Warrant liability	0	31,000
Total current liabilities	3,164,374	1,992,812
Non-current liabilities:
Lease liability, net of current portion	226,111	280,247
Total non-current liabilities	226,111	280,247
Total liabilities	3,390,485	2,273,059
Commitments and contingencies (see Note 9)
Stockholders' equity:
Preferred stock - $0.001 par value, 5 million shares authorized and 0 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively
Common stock, $0.001 par value, 150 million shares authorized, 46.5 million and 45.7 million shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	46,532	45,728
Additional paid-in capital	373,467,697	371,573,909
Accumulated deficit	(334,019,058)	(327,533,414)
Total stockholders' equity	39,495,171	44,086,223
Total liabilities and stockholders' equity	$ 42,885,656	$ 46,359,282

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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- Definition

Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.