v3.10.0.1
Statements of Cash Flows - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Cash flows from operating activities:    
Net loss $ (50,840,122) $ (49,376,875)
Adjustments to reconcile net loss to Net cash used in operating activities:    
Depreciation and amortization 1,054,720 1,309,980
Stock based compensation 16,753,754 15,802,819
Loss on sale of property and equipment   726
Amortization of prepaid rent from stock issuance to landlord 80,784 80,784
Changes in operating assets and liabilities:    
Accounts receivable (44,550) 149,500
Prepaid expenses and other current assets 445,270 348,275
Other assets 30,102 15,995
Accounts payable (163,305) (2,683,073)
Accrued expenses 156,324 53,530
Deferred revenue   (131,959)
Net cash used in operating activities (32,527,023) (34,430,298)
Cash flows from investing activities:    
Purchases of property and equipment (859,819) (817,448)
Proceeds from the sale of property and equipment   2,800
Net cash used in investing activities (859,819) (814,648)
Cash flows from financing activities:    
Net proceeds from the sales of common stock 38,846,815  
Net proceeds from issuance of shares to private investors   14,932,547
Proceeds from the exercise of stock options 1,319,461 979,950
Proceeds from contributions to employee stock purchase Plan 531,797 869,066
Net cash provided by financing activities 40,698,073 16,781,563
Net increase (decrease) in cash and cash equivalents 7,311,231 (18,463,383)
Cash and cash equivalents - beginning 12,795,254 31,258,637
Cash and cash equivalents - ending 20,106,485 12,795,254
Restricted Stock Units (RSUs) [Member]    
Supplemental disclosure of non-cash financing activities:    
Common stock issued 10 8
Performance Shares [Member]    
Supplemental disclosure of non-cash financing activities:    
Common stock issued $ 3 $ 1

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