Stockholders' Equity - Additional Information (Details) - USD ($)	21 Months Ended	25 Months Ended	37 Months Ended
	Aug. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	May 31, 2018	Jun. 30, 2016
Equity [Abstract]
Number of common shares authorized (shares)		300,000,000	300,000,000	175,000,000	300,000,000
Preferred stock, shares authorized (shares)		5,000,000	5,000,000
Shares of common stock issuable upon conversion or exercise of rights granted (shares)			5,000,000
Maximum proceeds to be raised	$ 250,000,000	$ 128,300,000.0	$ 202,100,000.0