XML 27 R34.htm IDEA: XBRL DOCUMENT v3.19.3
Loan and Security Agreement - Reconciliation of cash, cash equivalents, and restricted cash (Details) - USD ($)
Sep. 30, 2019
Dec. 31, 2018
Sep. 30, 2018
Dec. 31, 2017
Loan and Security Agreement        
Cash and cash equivalents $ 6,664,508 $ 8,077,539    
Restricted cash 5,000,000 5,000,000    
Cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 11,664,508 $ 13,077,539 $ 9,802,806 $ 3,210,749