Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Deferred income tax assets:      
Stock and other compensation expense $ 2,157 $ 2,252  
Net operating losses 14,169 11,787  
Research and development credits 1,676 1,676  
Other federal, state and foreign carryforwards 2,458 2,424  
Intangible assets 2,221 1,765  
Other 459 620  
Gross deferred tax assets 23,140 20,524  
Valuation allowances (19,333) (14,025)  
Net deferred tax assets 3,807 6,499  
Deferred income tax liabilities:      
Fixed assets (2,380) (5,139)  
Intangible assets and other (1,300) (1,007)  
Gross deferred tax liabilities (3,680) (6,146)  
Subtotal 127 353  
Less unrecognized tax benefit liability related to deferred items (628) (628) $ (600)
Net deferred tax liabilities $ (501) $ (275)