Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (77,785,576)	$ (49,244,511)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of debt discount	0	15,149
Depreciation and amortization	2,113,865	1,024,845
Net accretion of bond discounts/premiums	1,404,626	(109,870)
Gain on sale of marketable securities	(327,025)	0
Amortization of right to use assets	624,614	506,855
Stock-based compensation	22,121,591	15,091,269
Changes in operating assets and liabilities:
Account receivable	(2,444,450)	2,716,501
Other receivables	2,769,195	(2,886,261)
Prepaid expenses and other current assets	265,412	(1,282,866)
Accounts payable	(246,733)	(618,960)
Accrued expenses	4,540,830	2,225,695
Deferred revenue	(13,102,948)	8,513,945
Operating lease liabilities	(669,183)	(399,610)
Net cash used in operating activities	(60,735,782)	(24,447,819)
Cash flows from investing activities:
Purchase of marketable securities	(41,196,165)	(113,056,097)
Maturities of marketable securities	115,402,053	119,842,816
Sales of marketable securities	37,775,235	0
Purchase of property, equipment and leasehold improvements	(4,592,917)	(4,455,360)
Net cash provided by investing activities	107,388,206	2,331,359
Cash flows from financing activities:
Repayments of long-term debt	0	(169,610)
Proceeds from sale of common stock in at-the-market offering	30,835,206	0
Payment of common stock offering costs	(916,704)	0
Proceeds from issuance of common stock	0	29,454,033
Proceeds from exercise of stock options	3,206,938	1,777,456
Net cash provided by financing activities	33,125,440	31,061,879
Net increase in cash and cash equivalents	79,777,864	8,945,419
Cash and cash equivalents, beginning of the period	9,211,057	3,190,056
Cash and cash equivalents, end of the period	88,988,921	12,135,475
Supplemental disclosure of cash flow information:
Purchases of property, equipment and leasehold improvements unpaid at period end	777,940	138,600
Cash paid for interest	$ 48,750	$ 59,586