Basis and Summary of Significant Accounting Policies - Investments (Details) £ / shares in Units, £ in Millions |
1 Months Ended | 3 Months Ended | |||||
|---|---|---|---|---|---|---|---|
|
Dec. 05, 2017
£ / shares
|
Dec. 31, 2017
GBP (£)
|
Mar. 31, 2018
USD ($)
|
Mar. 31, 2017
USD ($)
|
Mar. 31, 2018
GBP (£)
|
Mar. 31, 2018
USD ($)
|
Dec. 31, 2017
USD ($)
|
|
| Significant Accounting Policies [Line Items] | |||||||
| Payment of outstanding note balance | £ | £ 2.0 | ||||||
| Proceeds from Investments | $ 666,000 | $ 0 | |||||
| Variable Interest Entity, Not Primary Beneficiary | |||||||
| Significant Accounting Policies [Line Items] | |||||||
| Held-to-maturity securities | £ 15.1 | £ 14.6 | $ 20,500,000 | $ 20,400,000 | |||
| Investment interest rate | 12.00% | 12.00% | |||||
| Asset impairment charges | $ 0 | ||||||
| Perfect Home Warrant | |||||||
| Significant Accounting Policies [Line Items] | |||||||
| Issuance of warrant price per share (in GBP per share) | £ / shares | £ 0.00001 | ||||||