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Marketable Securities (Details) - USD ($)
Jun. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Marketable securities $ 9,479,686 $ 8,290,679
U.S. Treasury notes and bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 5,155,696 5,034,955
Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 0 2,504,551
Commercial paper    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 2,265,824 0
Short-term cash investments    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 2,058,166 751,173
Level 1    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 5,155,696 5,034,955
Level 1 | U.S. Treasury notes and bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 5,155,696 5,034,955
Level 1 | Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 0 0
Level 1 | Commercial paper    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities   0
Level 1 | Short-term cash investments    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 0 0
Level 2    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 4,323,990 3,255,724
Level 2 | U.S. Treasury notes and bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 0 0
Level 2 | Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 0 2,504,551
Level 2 | Commercial paper    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities 2,265,824 0
Level 2 | Short-term cash investments    
Debt Securities, Available-for-sale [Line Items]    
Marketable securities $ 2,058,166 $ 751,173