Cash, cash equivalents and short-term investments - Summary of cash, cash equivalents and short-term investments (Details) - USD ($)
$ in Thousands |
Dec. 31, 2019 |
Jun. 30, 2019 |
Dec. 31, 2018 |
| Debt Securities, Available-for-sale [Line Items] |
|
|
|
| Cash |
$ 20,824
|
$ 25,987
|
|
| Total cash equivalents |
5,523
|
1,288
|
|
| Total cash and cash equivalents |
26,347
|
27,275
|
$ 22,405
|
| Debt securities |
|
|
|
| Amortized Cost |
102,139
|
70,493
|
|
| Unrealized Gains |
488
|
404
|
|
| Unrealized Losses |
(24)
|
(43)
|
|
| Estimated Fair Value |
102,603
|
70,854
|
|
| Marketable equity securities |
|
|
|
| Amortized Cost |
|
250
|
|
| Unrealized Gains |
|
1,099
|
|
| Unrealized Losses |
|
0
|
|
| Estimated Fair Value |
|
1,349
|
|
| Short-term investments |
|
|
|
| Amortized Cost |
|
70,743
|
|
| Unrealized Gains |
|
1,503
|
|
| Unrealized Losses |
|
(43)
|
|
| Estimated Fair Value |
102,603
|
72,203
|
|
| Cash, cash equivalents and short-term investments |
|
|
|
| Amortized Cost |
128,486
|
98,018
|
|
| Unrealized Gains |
488
|
1,503
|
|
| Unrealized Losses |
(24)
|
(43)
|
|
| Estimated Fair Value |
128,950
|
99,478
|
|
| U.S. treasury securities |
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
2,618
|
3,570
|
|
| Unrealized Gains |
9
|
6
|
|
| Unrealized Losses |
0
|
(4)
|
|
| Estimated Fair Value |
2,627
|
3,572
|
|
| U.S. agency securities |
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
3,815
|
3,002
|
|
| Unrealized Gains |
6
|
9
|
|
| Unrealized Losses |
(2)
|
(2)
|
|
| Estimated Fair Value |
3,819
|
3,009
|
|
| Asset-backed securities |
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
20,446
|
12,319
|
|
| Unrealized Gains |
93
|
104
|
|
| Unrealized Losses |
(19)
|
(10)
|
|
| Estimated Fair Value |
20,520
|
12,413
|
|
| Municipal securities |
|
|
|
| Debt Securities, Available-for-sale [Line Items] |
|
|
|
| Total cash equivalents |
750
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
8,930
|
4,124
|
|
| Unrealized Gains |
27
|
16
|
|
| Unrealized Losses |
0
|
0
|
|
| Estimated Fair Value |
8,957
|
4,140
|
|
| Commercial paper |
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
3,676
|
1,986
|
|
| Unrealized Gains |
1
|
0
|
|
| Unrealized Losses |
0
|
0
|
|
| Estimated Fair Value |
3,677
|
1,986
|
|
| Corporate bonds |
|
|
|
| Debt securities |
|
|
|
| Amortized Cost |
62,654
|
45,492
|
|
| Unrealized Gains |
352
|
269
|
|
| Unrealized Losses |
(3)
|
(27)
|
|
| Estimated Fair Value |
63,003
|
45,734
|
|
| Money market mutual funds |
|
|
|
| Debt Securities, Available-for-sale [Line Items] |
|
|
|
| Total cash equivalents |
4,274
|
790
|
|
| Commercial paper |
|
|
|
| Debt Securities, Available-for-sale [Line Items] |
|
|
|
| Total cash equivalents |
$ 499
|
$ 498
|
|