Redeemable Convertible Preferred Stock and Common Stock - Additional Information (Details)		6 Months Ended
	Jan. 12, 2018	Jun. 30, 2018 $ / shares shares	Jan. 31, 2018 shares	Jan. 30, 2018 shares	Dec. 31, 2017 $ / shares shares
Temporary Equity [Line Items]
Preferred stock, shares authorized		10,000,000			0
Preferred stock, shares authorized					20,320,667
Preferred stock, shares issued		0			0
Preferred stock, shares outstanding		0			0
Reverse stock split description	one-for-1.2804	one-for-1.2804
Reverse stock split ratio	0.781
Initial Public Offering
Temporary Equity [Line Items]
Preferred stock, shares authorized				10,000,000
Convertible preferred stock converted into common stock				15,870,559
Initial Public Offering | Common Stock
Temporary Equity [Line Items]
Convertible preferred stock converted into common stock			15,870,559
Series A Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares authorized		0			15,527,951
Preferred stock, shares issued		0			15,527,951
Preferred stock, shares outstanding		0			15,527,951
Preferred stock, par value | $ / shares		$ 0.0001			$ 0.0001
Series B Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares authorized		0			4,792,716
Preferred stock, shares issued		0			4,792,716
Preferred stock, shares outstanding		0			4,792,716
Preferred stock, par value | $ / shares		$ 0.0001			$ 0.0001