XML 74 R56.htm IDEA: XBRL DOCUMENT v3.6.0.2
Income Taxes - Tax Effects (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Income Tax Disclosure [Abstract]      
Pretax loss $ 31,400 $ 33,700 $ 29,400
Provision for income taxes 0 0 0
Reconciliation of tax expense computed at the statutory federal rate and the Company's tax expense      
U.S. federal taxes at statutory rate (10,662) (11,459) (9,987)
State tax (net of federal benefit) 20 (30) 5
Permanent differences 153 96 64
Incentive stock options 1,095 789 672
Tax credits (677) (581) (461)
Change in valuation allowance 10,071 11,185 9,707
Total provision for income taxes 0 0 0
Non-current deferred tax assets:      
Net operating loss carryforwards 61,674 52,262 41,971
Research and development credits 3,174 2,497 1,916
Stock-based compensation 2,847 1,825 826
Genzyme co-promotion agreement 0 330 995
Accruals, deferred rent and other 4,511 4,698 3,381
Gross deferred tax assets 72,206 61,612 49,089
Valuation allowance (65,975) (55,101) (43,439)
Net deferred tax assets 6,231 6,511 5,650
Deferred tax liabilities:      
Property and equipment (1,180) (1,215) (60)
In-process research and development (5,051) (5,296) (5,590)
Gross deferred tax liabilities (6,231) (6,511) (5,650)
Net deferred tax liabilities (6,231) (6,511) (5,650)
Increase in valuation allowance against deferred tax assets 10,900 $ 11,700 $ 10,600
Operating loss carryforwards      
Federal and state net operating loss carryforwards related to stock-based compensation 1,600    
Federal      
Operating loss carryforwards      
Net operating loss carryforwards 169,100    
State      
Operating loss carryforwards      
Net operating loss carryforwards $ 84,200