Cash Equivalents and Investments (Footnote) (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Short-term Investments | Certificates of deposit and money market deposit accounts | Minimum
Cash and Cash Equivalents [Line Items]
Securities maturity period	1 month	1 month
Short-term Investments | Certificates of deposit and money market deposit accounts | Maximum
Cash and Cash Equivalents [Line Items]
Securities maturity period	12 months	12 months
Other assets | Certificates of deposit and money market deposit accounts | Minimum
Cash and Cash Equivalents [Line Items]
Securities maturity period	13 months	13 months
Other assets | Certificates of deposit and money market deposit accounts | Maximum
Cash and Cash Equivalents [Line Items]
Securities maturity period	23 months	18 months
Cash and Cash Equivalents | Mutual funds | Maximum
Cash and Cash Equivalents [Line Items]
Securities maturity period	90 days