Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Current deferred tax assets:    
Total $ 514 $ 504
Non-current deferred tax assets:    
Total 4,237 3,357
Valuation allowance (4,751) (3,861)
Net deferred tax assets 0 0
Deferred Tax Current [Member]    
Current deferred tax assets:    
Allowance for bad debts 34 34
Share-based payment expense 321 220
Allowance for obsolete inventory 30 98
Accrued compensation 63 77
Contribution carryover   2
Other accruals 66 73
Deferred Tax Non-current [Member]    
Non-current deferred tax assets:    
Depreciation 16 11
Capital loss 179 179
Net operating loss 3,991 3,118
Credit carryover $ 51 $ 49