Cash Equivalents, Restricted Cash and Investments - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 333,205	$ 39,179
Total cash, cash equivalents and restricted cash	334,285	40,259	$ 38,745	$ 28,088
Other Assets [Member]
Restricted cash included in Other assets	$ 1,080	$ 1,080