UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounts receivable, net
Allowances for accounts receivables	$ 192	$ 124
Convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.001
Convertible preferred stock, shares authorized (in shares)	25,000,000
Convertible preferred stock, shares issued (in shares)	0
Convertible preferred stock, shares outstanding (in shares)	0
Common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares (in shares)	500,000,000	156,650,000
Common stock, shares issued (in shares)	67,809,071	11,193,366
Common stock, shares outstanding (in shares)	67,753,667	11,139,690
Treasury stock
Treasury stock, shares (in shares)	55,404	53,676
Redeemable convertible preferred stock
Convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized (in shares)	0	94,101,207
Convertible preferred stock, shares issued (in shares)	0	88,741,194
Convertible preferred stock, shares outstanding (in shares)	0	88,741,194
Convertible preferred stock, liquidation preference, value		$ 272,506
Series A convertible preferred stock
Convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized (in shares)	0	8,800,000
Convertible preferred stock, shares issued (in shares)	0	3,851,806
Convertible preferred stock, shares outstanding (in shares)	0	3,851,806