Warrants - Additional Information (Details)		1 Months Ended	12 Months Ended
	Jan. 15, 2015 USD ($) $ / shares shares	Aug. 31, 2014 Institution	Dec. 31, 2018 $ / shares	Dec. 31, 2016 Institution	Mar. 31, 2016 $ / shares shares	May 11, 2015 $ / shares shares	Aug. 22, 2014 $ / shares shares
Growth Term Loan
Class Of Warrant Or Right [Line Items]
Number of loan lending institutions | Institution		2		2
Series E Redeemable Convertible Preferred Stock
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares | shares					5,317	23,396	2,512,562
Warrants exercise price | $ / shares			$ 23.51		$ 23.51	$ 23.51	$ 0.2189
Warrants expiration date			Aug. 22, 2024
Common Stock Warrants one
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares | shares					45,307
Warrants exercise price | $ / shares			$ 6.45		$ 2.759
Convertible Note Warrants
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares | shares	9,311,586
Warrants exercise price | $ / shares	$ 0.2189		$ 14.00
Warrants expiration date			Jan. 15, 2022
Aggregate consideration | $	$ 1,354
Convertible Note Warrants | IPO
Class Of Warrant Or Right [Line Items]
Warrants issued to acquire shares | shares						144,772
Warrants exercise price | $ / shares						$ 14.00