Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net loss	$ (33,091,014)	$ (43,450,124)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,539,294	1,725,501
Depreciation and amortization	2,047,854	1,135,550
Amortization of discount on long-term debt and convertible notes		17,550,541
Non-cash interest expense	32,180	339,504
Warrant fair value adjustment		(277,715)
Non-cash rent (income) expense		(154,395)
Changes in operating assets and liabilities:
Accounts receivable - trade and other	262,999	1,540,253
Prepaid expenses and other current assets	(267,414)	(88,979)
Other non-current assets	1,437,416	2,270,929
Accounts payable	1,353,762	(1,711,787)
Accrued expenses	77,630	(1,000,939)
Accrued compensation	(252,436)	(85,633)
Operating lease liabilities	(290,492)
Deferred revenue	(8,071,920)	(1,294,682)
Net cash used in operating activities	(34,222,141)	(23,501,976)
Investing activities
Purchases of property, plant and equipment	(1,716,208)	(769,870)
Net cash used in investing activities	(1,716,208)	(769,870)
Financing activities
Principal payments on finance leases		(480,940)
Principal payments on finance leases	(696,875)
Proceeds from issuance of long-term debt	5,000,000
Refund of principal payments on long-term debt		588,889
Principal payments on long-term debt		(2,433,680)
Payments for debt issuance costs		(392,000)
Proceeds from issuance of Series D preferred stock, net of issuance costs		25,106,896
Proceeds from public offering of common stock, net of underwriting fees and commissions	31,872,808	47,320,584
Payments for offering costs	(610,007)	(1,628,090)
Proceeds from exercise of stock options and warrants	142,002	286,998
Net cash provided by financing activities	35,707,928	68,368,657
Net increase (decrease) in cash	(230,421)	44,096,811
Cash, beginning of period	39,534,985	3,418,979
Cash, end of period	39,304,564	47,515,790
Supplemental disclosure of cash flow information
Cash paid for interest	705,249	869,033
Cash paid for operating lease liabilities	790,688
Right of use assets obtained with lease liabilities	354,791
Purchase of equipment with leases		456,517
Changes in purchases of equipment in accounts payable	187,086	145,473
Purchase of build-to-suit asset with deferred financing obligation		272,656
Reclassification of deferred financing obligation to long-term debt		277,009
Reclassification of financing costs on deferred financing obligation to discount on long-term debt		1,614,466
Accrued tenant improvements and receivable from landlord	936,104
Conversion of accrued interest to long-term debt		106,558
Conversion of convertible notes and accrued interest into Series D preferred stock		28,877,498
Deferred offering costs incurred but not paid	$ 141,314	340,069
Exercise of stock options through exchange of vested stock options		$ 162,156