Fair Value Measurements (Tables)
3 Months Ended
Mar. 31, 2021
Fair Value Disclosures [Abstract]  
Summary of Assets Measured at Fair Value on Recurring Basis

The following table summarizes the assets measured at fair value on a recurring basis as of March 31, 2021 and December 31, 2020, by level within the fair value hierarchy:

 

    March 31, 2021  
    (Level 1)     (Level 2)     (Level 3)     Total  
Marketable investment securities:                                
Certificates of deposit   $ -     $ 2,302,644     $ -     $ 2,302,644  

 

    December 31, 2020  
    (Level 1)     (Level 2)     (Level 3)     Total  
Marketable investment securities:                                
Certificates of deposit   $ -     $ 4,335,446     $ -     $ 4,335,446