Redeemable Convertible Preferred Stock and Stockholders' Deficit - Narrative (Details)	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 $ / shares shares
Class of Stock [Line Items]
Underwritten public offering proceeds (greater than) | $	$ 50,000
Percent of outstanding redeemable convertible preferred stock	0.67
Common stock, authorized (in shares) | shares	290,081,638	290,081,638
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Series A-1
Class of Stock [Line Items]
Preferred stock, issued, original price	0.3426
Preferred stock, dividend rate (in dollars per share)	0.0273
Series A-2
Class of Stock [Line Items]
Preferred stock, issued, original price	0.2913
Preferred stock, dividend rate (in dollars per share)	0.0234
Series A-3
Class of Stock [Line Items]
Preferred stock, issued, original price	0.0855
Preferred stock, dividend rate (in dollars per share)	0.0069
Series B
Class of Stock [Line Items]
Preferred stock, issued, original price	0.6603
Preferred stock, dividend rate (in dollars per share)	0.0528
Series C
Class of Stock [Line Items]
Preferred stock, issued, original price	1.0782
Preferred stock, dividend rate (in dollars per share)	0.0864
Series D
Class of Stock [Line Items]
Preferred stock, issued, original price	1.0782
Preferred stock, dividend rate (in dollars per share)	0.0864
Series E
Class of Stock [Line Items]
Preferred stock, issued, original price	3.7182
Preferred stock, dividend rate (in dollars per share)	0.2976
Series F
Class of Stock [Line Items]
Preferred stock, issued, original price	7.2858
Preferred stock, dividend rate (in dollars per share)	0.5829
Series G
Class of Stock [Line Items]
Preferred stock, issued, original price	9.8931
Preferred stock, dividend rate (in dollars per share)	$ 0.7914