Fair Value Measurement - Additional Information (Details) - USD ($)	Sep. 30, 2018	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Investments	$ 0	$ 3,601,000

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

No definition available.

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant