Convertible and Redeemable Convertible Preferred Stock - Components of Convertible and Redeemable Convertible Preferred Stock (Detail) - USD ($)
$ / shares in Units, $ in Thousands |
Jun. 30, 2015 |
Dec. 31, 2014 |
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
136,074,466
|
135,913,741
|
| Shares Issued |
17,357,903
|
17,266,628
|
| Net Carrying Value |
$ 297,652
|
$ 144,375
|
| Aggregate Liquidation Preference |
110,410
|
106,036
|
| Redemption Value |
$ 295,109
|
$ 141,832
|
| Shares Outstanding |
17,357,903
|
17,266,628
|
| Series A Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
1,843,894
|
1,843,894
|
| Shares Issued |
224,564
|
224,564
|
| Net Carrying Value |
$ 2,543
|
$ 2,543
|
| Liquidation Price Per Share |
$ 11.324
|
$ 11.324
|
| Aggregate Liquidation Preference |
$ 2,543
|
$ 2,543
|
| Shares Outstanding |
224,564
|
224,564
|
| Series B Redeemable Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
13,134,880
|
13,134,880
|
| Shares Issued |
1,752,634
|
1,752,634
|
| Net Carrying Value |
$ 42,688
|
$ 19,504
|
| Liquidation Price Per Share |
$ 12.755
|
$ 12.268
|
| Aggregate Liquidation Preference |
$ 22,355
|
$ 21,502
|
| Redemption Value |
$ 42,688
|
$ 19,504
|
| Shares Outstanding |
1,752,634
|
1,752,634
|
| Series B-1 Redeemable Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
16,283,343
|
16,122,618
|
| Shares Issued |
1,478,328
|
1,392,300
|
| Net Carrying Value |
$ 24,596
|
$ 6,979
|
| Liquidation Price Per Share |
$ 3.742
|
$ 3.656
|
| Aggregate Liquidation Preference |
$ 5,532
|
$ 5,091
|
| Redemption Value |
$ 24,596
|
$ 6,979
|
| Shares Outstanding |
1,478,328
|
1,392,300
|
| Series C Redeemable Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
19,812,349
|
19,812,349
|
| Shares Issued |
2,493,017
|
2,487,770
|
| Net Carrying Value |
$ 41,493
|
$ 21,052
|
| Liquidation Price Per Share |
$ 5.865
|
$ 5.642
|
| Aggregate Liquidation Preference |
$ 14,621
|
$ 14,035
|
| Redemption Value |
$ 41,493
|
$ 21,052
|
| Shares Outstanding |
2,493,017
|
2,487,770
|
| Series D Redeemable Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
85,000,000
|
85,000,000
|
| Shares Issued |
11,409,360
|
11,409,360
|
| Net Carrying Value |
$ 186,332
|
$ 94,297
|
| Liquidation Price Per Share |
$ 5.728
|
$ 5.510
|
| Aggregate Liquidation Preference |
$ 65,359
|
$ 62,865
|
| Redemption Value |
$ 186,332
|
$ 94,297
|
| Shares Outstanding |
11,409,360
|
11,409,360
|
| Redeemable Convertible Preferred Stock [Member] |
|
|
| Temporary Equity [Line Items] |
|
|
| Shares Authorized |
134,230,572
|
134,069,847
|
| Shares Issued |
17,133,339
|
17,042,064
|
| Net Carrying Value |
$ 295,109
|
$ 141,832
|
| Aggregate Liquidation Preference |
107,867
|
103,493
|
| Redemption Value |
$ 295,109
|
$ 141,832
|
| Shares Outstanding |
17,133,339
|
17,042,064
|