Investments - Summary of Investments Included in Cash Equivalents and Short Term Investments (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Amortized Cost	$ 115,557,389	$ 122,338,668
Unrealized Loss	(86,165)	(73,308)
Fair Value	115,471,224	122,265,360
Asset-backed Securities
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Cash equivalents and short-term investments, Amortized Cost	8,099,245	7,428,021
Cash equivalents and short-term investments, Unrealized Loss	(8,721)	(6,318)
Cash equivalents and short-term investments, Fair Value	8,090,524	7,421,703
Money market funds
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Cash equivalents and short-term investments, Amortized Cost	28,831,110	44,181,756
Cash equivalents and short-term investments, Fair Value	28,831,110	44,181,756
Commercial Paper
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Cash equivalents and short-term investments, Amortized Cost	32,277,246	34,882,298
Cash equivalents and short-term investments, Fair Value	32,277,246	34,882,298
Corporate Debt Securities
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Cash equivalents and short-term investments, Amortized Cost	21,433,498	26,905,815
Cash equivalents and short-term investments, Unrealized Loss	(53,474)	(49,532)
Cash equivalents and short-term investments, Fair Value	21,380,024	26,856,283
U.S Treasury Securities
Schedule Of Cash Cash Equivalents And Available For Sale Securities [Line Items]
Cash equivalents and short-term investments, Amortized Cost	24,916,290	8,940,778
Cash equivalents and short-term investments, Unrealized Loss	(23,970)	(17,458)
Cash equivalents and short-term investments, Fair Value	$ 24,892,320	$ 8,923,320