Net Loss Per Share - Schedule of Number of Shares of Common Stock Underlying Potentially Dilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	677,074	1,919,247
Convertible Promissory Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities		188,593
Convertible redeemable preferred stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities		1,608,654
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	10,974
Options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	666,100	122,000