Convertible preferred stock (Details) - USD ($)
$ / shares in Units, $ in Thousands |
1 Months Ended |
12 Months Ended |
48 Months Ended |
|
Feb. 28, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Dec. 31, 2014 |
Dec. 31, 2015 |
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
141,131,524
|
|
141,131,524
|
0
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
141,131,524
|
|
141,131,524
|
0
|
| Shares outstanding |
|
141,131,524
|
|
141,131,524
|
0
|
| Aggregate liquidation amount |
|
$ 207,002
|
|
$ 207,002
|
|
| Proceeds, net of issuance costs |
|
$ 115,731
|
$ 49,819
|
$ 202,305
|
|
| Number of common stock shares converted from preferred stock |
23,521,889
|
|
|
|
|
| Series A convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
11,693,179
|
|
11,693,179
|
|
| Original issue price |
|
$ 0.44
|
|
$ 0.44
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
11,693,179
|
|
11,693,179
|
|
| Shares outstanding |
|
11,693,179
|
|
11,693,179
|
|
| Aggregate liquidation amount |
|
$ 5,145
|
|
$ 5,145
|
|
| Proceeds, net of issuance costs |
|
$ 5,109
|
|
|
|
| Series B convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
4,181,818
|
|
4,181,818
|
|
| Original issue price |
|
$ 0.55
|
|
$ 0.55
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
4,181,818
|
|
4,181,818
|
|
| Shares outstanding |
|
4,181,818
|
|
4,181,818
|
|
| Aggregate liquidation amount |
|
$ 2,300
|
|
$ 2,300
|
|
| Proceeds, net of issuance costs |
|
$ 2,253
|
|
|
|
| Series C convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
31,112,750
|
|
31,112,750
|
|
| Original issue price |
|
$ 0.95
|
|
$ 0.95
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
31,112,750
|
|
31,112,750
|
|
| Shares outstanding |
|
31,112,750
|
|
31,112,750
|
|
| Aggregate liquidation amount |
|
$ 29,557
|
|
$ 29,557
|
|
| Proceeds, net of issuance costs |
|
$ 29,393
|
|
|
|
| Series D convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
8,000,000
|
|
8,000,000
|
|
| Original issue price |
|
$ 1.25
|
$ 1.25
|
$ 1.25
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
8,000,000
|
8,000,000
|
8,000,000
|
|
| Shares outstanding |
|
8,000,000
|
|
8,000,000
|
|
| Aggregate liquidation amount |
|
$ 10,000
|
|
$ 10,000
|
|
| Proceeds, net of issuance costs |
|
$ 9,933
|
|
|
|
| Series E convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
26,143,777
|
|
26,143,777
|
|
| Original issue price |
|
$ 1.53
|
$ 1.53
|
$ 1.53
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
26,143,777
|
26,143,777
|
26,143,777
|
|
| Shares outstanding |
|
26,143,777
|
|
26,143,777
|
|
| Aggregate liquidation amount |
|
$ 40,000
|
|
$ 40,000
|
|
| Proceeds, net of issuance costs |
|
$ 39,886
|
|
|
|
| Series F convertible preferred stock |
|
|
|
|
|
| Convertible preferred stock |
|
|
|
|
|
| Shares authorized |
|
60,000,000
|
|
60,000,000
|
|
| Original issue price |
|
$ 2.00
|
|
$ 2.00
|
|
| Issuance of convertible preferred stock, net of issuance costs (in shares) |
|
60,000,000
|
|
60,000,000
|
|
| Shares outstanding |
|
60,000,000
|
|
60,000,000
|
|
| Aggregate liquidation amount |
|
$ 120,000
|
|
$ 120,000
|
|
| Proceeds, net of issuance costs |
|
$ 115,731
|
|
|
|