Related Party Transactions - Additional Information (Detail)	Dec. 31, 2018
Silver Creek [Member] \| Series A and B Preferred Stock [Member]
Related Party Transaction [Line Items]
Shares owned by employees and directors of the parent company (as a percent)	4.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration