Stockholder's Deficit - Schedule of Reserved Shares of Common Stock for Future Issuances (Details) shares in Thousands	Mar. 31, 2018 shares
Class Of Stock [Line Items]
Total reserved shares of common stock	42,029
Equity Incentive Plan
Class Of Stock [Line Items]
Common stock awards granted under equity incentive plans	24,933
Common stock awards available for grant under equity incentive plan	17,096