Quarterly report pursuant to Section 13 or 15(d)

Restricted Cash - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details)

v3.19.1
Restricted Cash - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)
Mar. 31, 2019
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2017
Restricted Cash And Investments [Abstract]        
Cash and cash equivalents $ 15,037,639 $ 11,376,373    
Restricted cash 25,980 25,980    
Cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows $ 15,063,619 $ 11,402,353 $ 16,668,738 $ 18,631,784