Consolidated Statements of Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (16,453,918)	$ (18,960,017)
Other comprehensive income (loss), net of tax effect:
Unrealized gain (loss) on short-term investments	(2,308)	1,090
Foreign currency translation adjustment	(1,145)
Total other comprehensive income (loss)	(3,453)	1,090
Comprehensive loss	$ (16,457,371)	$ (18,958,927)