CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 263	$ 268
Redeemable convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock authorized (in shares)	0	12,104,749
Redeemable convertible preferred stock issued (in shares)	0	11,871,578
Redeemable convertible preferred stock outstanding (in shares)	0	11,871,578
Redeemable convertible preferred stock, liquidation preference	$ 0	$ 119,194
Preferred stock, par value (in dollars per share)	$ 0.0001
Preferred stock authorized (in shares)	5,000,000
Preferred stock issued (in shares)	0
Preferred stock outstanding (in shares)	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	100,000,000	19,333,333
Common stock issued (in shares)	24,450,757	3,603,140
Common stock outstanding (in shares)	24,450,757	3,603,140