v3.19.3
Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Mar. 31, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Operating activities:            
Net loss       $ (21,914,475) $ (12,084,936)  
Adjustments to reconcile net loss to net cash used by operating activities:            
Depreciation $ 278,182 $ 391,246   814,984 1,169,801  
Change in fair value of preferred stock warrants and expirations 0 (1,520,159)   0 (3,991,081)  
Interest payment-in-kind       319,401 0  
Stock-based compensation       989,521 160,551  
Provision for bad debt expense       0 (262,000)  
Accretion of debt discount       204,259 121,984  
Loss on debt extinguishment 0 0   921,496 342,164  
Long-term debt prepayment fees     $ 0 412,000    
Employee stock purchase plan compensation       102,815 0  
Inventory write-off       0 1,287,000  
Changes in operating assets and liabilities:            
Accounts receivable       (1,486,450) (386,710)  
Inventory       (1,886,083) (2,101,453)  
Prepaid expenses and other current assets       98,102 (276,263)  
Accounts payable       1,042,103 60,788  
Accrued expenses and other liabilities       337,139 106,476  
Net cash used in operating activities       (20,045,188) (15,853,679) $ 19,900,000
Investing activities:            
Purchases of property and equipment       (38,390) (319,885)  
Net cash used in investing activities       (38,390) (319,885)  
Financing activities:            
Repayment of long-term debt       (10,812,000) (7,447,571)  
Proceeds from issuance of long-term debt, net of issuance costs       19,169,903 9,532,957  
Proceeds from issuance of convertible note, net of issuance costs       0 14,329,843  
Proceeds from borrowing on line of credit       3,084,340 0  
Repayments of borrowing from line of credit       (2,131,246) 0  
Proceeds from sale of common stock, net of offering costs       2,409,593 0  
Proceeds from Initial Public Offering, net of offering costs       0 19,389,978  
Proceeds from option exercises       65,060 3,499  
Net cash provided by financing activities       11,785,650 35,808,706  
Net (decrease) increase in cash and cash equivalents       (8,297,928) 19,635,142  
Cash and cash equivalents at beginning of period     $ 1,021,897 16,522,729 1,021,897 1,021,897
Cash and cash equivalents at end of period $ 8,224,801 $ 20,657,038   8,224,801 20,657,038 $ 16,522,729
Supplemental schedule on non-cash transactions:            
Property and equipment costs incurred but not paid included in accounts payable and accrued expenses       7,687 0  
Transfer of instruments from property and equipment into inventory       0 106,617  
Fair value of warrants issued with debt classified as a liability       629,830 176,813  
Transfer of instruments and servers from inventory to property and equipment       359,545 0  
Fair value of stock issued with debt classified as a liability       201,789 0  
Deferred equity issuance costs in accounts payable and accrued liabilities       197,291 0  
Debt issuance costs in accounts payable and accrued liabilities       35,458 0  
Conversion of convertible note into common stock       0 14,898,326  
Conversion of preferred stock warrants into common stock and common stock warrants       0 84,676  
Final payment due in connection with the repayment of debt classified in other long-term liabilities       $ 0 $ 400,000