At-The-Market Offering - Additional Information (Detail) - Stifel, Nicolaus & Company, Incorporated - USD ($) $ in Millions		6 Months Ended
	Dec. 28, 2018	Jun. 30, 2019
Stockholders Equity Common Stock [Line Items]
Percentage of commission paid	3.00%
Total shares of common stock sold (in shares)		0
Maximum
Stockholders Equity Common Stock [Line Items]
Sale of common stock in an at-the-market offering	$ 75.0