Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v3.6.0.2
Income Taxes - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Jan. 01, 2016
Income Tax Contingency [Line Items]        
Tax expense (benefit) for change in valuation allowance $ 968,000 $ 1,164,000 $ 1,223,000  
Valuation allowance 767,000 1,735,000    
Unrecognized tax benefits, interest or penalties recognized 0 0 0  
Unrecognized tax benefits that, if recognized, would affect the effective tax rate 934,000 $ 773,000 $ 577,000  
California        
Income Tax Contingency [Line Items]        
Net operating loss carryforwards 7,035,000      
Research and development credits carryforwards 1,885,000      
Tax expense (benefit) for change in valuation allowance 968,000      
Valuation allowance 767,000      
Tax effected 410,000      
Federal        
Income Tax Contingency [Line Items]        
Net operating loss carryforwards $ 36,925,000      
Net operating loss carryforwards expiration, beginning year 2026      
Research and development credits carryforwards $ 1,849,000      
Research and development credits carryforwards expiration, beginning year 2022      
State        
Income Tax Contingency [Line Items]        
Net operating loss carryforwards $ 20,174,000      
Net operating loss carryforwards expiration, beginning year 2017      
ASU 2016-09        
Income Tax Contingency [Line Items]        
Increase in deferred tax assets and retained earnings $ 12,226,000     $ 12,226,000
Discrete tax benefits recognized $ 6,042,000