Subsequent Events (Details) $ / shares in Units, $ in Thousands	Aug. 02, 2017 USD ($) $ / shares shares	Jul. 12, 2017	Jul. 27, 2017 shares	Jun. 30, 2017 shares	Dec. 31, 2016 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under stock-based compensation plan (in shares)				73,353,213	73,655,190
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued upon conversion (in shares)	55,422,002
Conversion basis	1
Subsequent Event | IPO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares sold in offering (in shares)	10,615,650
Offering price (in dollars per share) | $ / shares	$ 15.00
Net proceeds from stock offering | $	$ 144,143
Subsequent Event | Over-Allotment Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares sold in offering (in shares)	1,384,650
Subsequent Event | 2017 Equity Incentive Plan and 2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under stock-based compensation plan (in shares)			9,459,659
Number of annual increases in shares available for issuance (in years)		10 years
Subsequent Event | Amended and Restated 2004 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under stock-based compensation plan (in shares)			4,159,659
Subsequent Event | 2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under stock-based compensation plan (in shares)			3,700,000
Subsequent Event | 2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance under stock-based compensation plan (in shares)			1,600,000