XML 71 R59.htm IDEA: XBRL DOCUMENT v3.19.2
Fair Value Measurements - Schedule of Reconciliation of Changes In Fair Value of Convertible Debentures (Detail) - Convertible Debentures [Member]
$ in Thousands
6 Months Ended
Jun. 30, 2019
USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]  
Balance, December 31, 2018 $ 6,970
Fair value adjustment 4,440
Balance, June 30, 2019 $ 11,410