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Cash, Cash Equivalents and Short-Term Investments - Summary of Short-term Investments with Unrealized Losses (Details)
12 Months Ended
Dec. 31, 2017
USD ($)
Cash, Cash Equivalents and Short-Term Investments [Line Itmes]  
Less Than 12 Months, Estimated Fair Value $ 11,570,971
Less Than 12 Months, Unrealized Losses. (16,907)
US Treasury Securities  
Cash, Cash Equivalents and Short-Term Investments [Line Itmes]  
Less Than 12 Months, Estimated Fair Value 2,485,259
Less Than 12 Months, Unrealized Losses. (5,540)
Corporate Debt Securities  
Cash, Cash Equivalents and Short-Term Investments [Line Itmes]  
Less Than 12 Months, Estimated Fair Value 6,819,777
Less Than 12 Months, Unrealized Losses. (9,414)
Asset-backed Securities  
Cash, Cash Equivalents and Short-Term Investments [Line Itmes]  
Less Than 12 Months, Estimated Fair Value 2,265,935
Less Than 12 Months, Unrealized Losses. $ (1,953)