Annual report pursuant to Section 13 and 15(d)

Statements of Cash Flows

v3.8.0.1
Statements of Cash Flows - USD ($)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Cash flows from operating activities:      
Net loss $ (49,376,875) $ (45,817,394) $ (27,561,702)
Adjustments to reconcile net loss to Net cash used in operating activities:      
Depreciation and amortization 1,309,980 957,836 817,729
Stock based compensation 15,802,819 9,508,175 5,951,414
Loss on sale of property and equipment 726    
Amortization of prepaid rent from stock issuance to landlord 80,784 80,784 80,784
Changes in operating assets and liabilities:      
Accounts receivable 149,500 (149,500)  
Prepaid expenses and other current assets 348,275 (652,336) (157,769)
Other assets 15,995 2,823 (28,682)
Accounts payable (2,683,073) 2,382,790 608,962
Accrued expenses 53,530 492,616 283,530
Deferred revenue (131,959) 131,959  
Net cash used in operating activities (34,430,298) (33,062,247) (20,005,734)
Cash flows from investing activities:      
Purchases of property and equipment (817,448) (1,137,446) (1,032,795)
Proceeds from the sale of property and equipment 2,800    
Net cash used in investing activities (814,648) (1,137,446) (1,032,795)
Cash flows from financing activities:      
Proceeds from shares issued under shelf registration, net of underwriter's discount and offering expenses     19,048,456
Net proceeds from issuance of shares to private investors 14,932,547 34,788,311  
Proceeds from the exercise of stock options 979,950 382,351 65,647
Proceeds from contributions to employee stock purchase plan 869,066 727,784 289,787
Proceeds from the disgorgement of short-swing profit     12,611
Net cash provided by financing activities 16,781,563 35,585,766 19,416,501
Net (decrease) increase in cash and cash equivalents (18,463,383) 1,386,073 (1,622,028)
Cash and cash equivalents - beginning 31,258,637 29,872,564 31,494,592
Cash and cash equivalents - ending 12,795,254 31,258,637 29,872,564
Supplemental disclosure of non-cash financing activities:      
Common stock issued for services     147,900
Cashless exercise of warrants   5 1
Increase in accrued expenses for the purchase of property and equipment   299,500  
Restricted Stock Units (RSUs) [Member]      
Cash flows from financing activities:      
Shares repurchased for tax withholdings on vesting   (266,217)  
Supplemental disclosure of non-cash financing activities:      
Common stock issued 8 6 $ 3
Performance Shares [Member]      
Cash flows from financing activities:      
Shares repurchased for tax withholdings on vesting   (46,463)  
Supplemental disclosure of non-cash financing activities:      
Common stock issued $ 1 $ 2