Equity Award Plans - Options to Purchase Common Stock - Activity (Details) - Common Stock - USD ($)
$ / shares in Units, $ in Thousands |
3 Months Ended |
12 Months Ended |
Mar. 31, 2018 |
Dec. 31, 2017 |
| Number of Shares |
|
|
| Beginning balance (in shares) |
14,183,221
|
|
| Granted (in shares) |
1,804,105
|
|
| Exercised (in shares) |
(274,840)
|
|
| Forfeited (in shares) |
(343,697)
|
|
| Ending balance (in shares) |
15,368,789
|
14,183,221
|
| Weighted-Average Exercise Price |
|
|
| Beginning balance (in dollars per share) |
$ 4.89
|
|
| Granted (in dollars per share) |
7.46
|
|
| Exercised (in dollars per share) |
3.55
|
|
| Forfeited (in dollars per share) |
5.68
|
|
| Ending balance (in dollars per share) |
$ 5.19
|
$ 4.89
|
| Vested and expected to vest |
|
|
| Number of Shares - Vested and expected to vest (in shares) |
14,698,656
|
|
| Weighted-Average Exercise Price - Vested and expected to vest (in dollars per share) |
$ 5.14
|
|
| Weighted-Average Remaining Contractual Term - Vested and expected to vest (in years) |
7 years 3 months
|
|
| Aggregate Intrinsic Value - Vested and expected to vest |
$ 87,329
|
|
| Additional disclosures |
|
|
| Weighted-Average Remaining Contractual Term - Options, balance (in years) |
7 years 3 months 26 days
|
7 years 1 month 28 days
|
| Aggregate Intrinsic Value - Options, balance |
$ 90,459
|
$ 17,626
|
| Number of Shares - Options vested and exercisable (in shares) |
7,986,329
|
|
| Weighted-Average Exercise Price - Options vested and exercisable (in dollars per share) |
$ 4.27
|
|
| Weighted-Average Remaining Contractual Term - Options vested and exercisable (in years) |
5 years 11 months 23 days
|
|
| Aggregate Intrinsic Value - Options vested and exercisable |
$ 54,358
|
|