Commitments and contingencies - Lease agreements (Details) $ in Thousands |
1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended | 19 Months Ended | ||||
|---|---|---|---|---|---|---|---|---|---|
|
Jun. 30, 2018
USD ($)
ft²
Option
|
Apr. 30, 2016 |
Dec. 31, 2015
USD ($)
|
Sep. 30, 2018
USD ($)
|
Sep. 30, 2017
USD ($)
|
Sep. 30, 2018
USD ($)
|
Sep. 30, 2017
USD ($)
|
Dec. 31, 2016
USD ($)
|
Jun. 30, 2018
USD ($)
ft²
|
|
| Lease agreements | |||||||||
| Number of options to extend lease agreement (in years) | 5 years | ||||||||
| Monthly lease payments, inclusive of base rent and ancillary charges | $ 7 | ||||||||
| Prior notice period upon termination of lease | 9 months | ||||||||
| Base rent of monthly lease payments | $ 23 | $ 31 | |||||||
| Leased office space | ft² | 63,000 | ||||||||
| Lease rent commencement duration | 8 months | ||||||||
| Rentable office space | ft² | 106,000 | 106,000 | |||||||
| Lease term | 10 years | 10 years | |||||||
| Number of options to renewal the lease | Option | 2 | ||||||||
| Renewal period of lease | 5 years | 5 years | |||||||
| Annual rental payment | $ 2,373 | ||||||||
| Percentage of annual increase in lease rental expenses | 3.00% | 3.00% | |||||||
| Rent expense | $ 33 | $ 21 | $ 55 | $ 42 | |||||