Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Carrying value	$ 99,623,000	$ 139,890,000
Fair Value, Recurring Basis
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Financial assets, fair value	0	0
Financial liabilities, fair value	0	0
Fair Value, Nonrecurring Basis
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Financial assets, fair value	0
Financial liabilities, fair value	0
DEG Vietnam Loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Carrying value	10,000,000	11,250,000
Fair value	$ 10,213,000	11,100,000
DEG China Loan
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Carrying value		913,000
Fair value		$ 900,000