Income Taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Deferred tax assets: | ||
| Federal and state net operating loss carryforwards | $ 37,411 | $ 33,846 |
| Tax credit carryforwards | 7,573 | 3,350 |
| Intangible assets | 56 | 197 |
| Stock-based compensation | 1,059 | 247 |
| Leasehold incentive | 240 | 467 |
| Other | 1,237 | 1,605 |
| Total deferred tax assets | 47,576 | 39,712 |
| Less valuation allowance | $ (47,576) | (39,624) |
| Net deferred tax assets | 88 | |
| Deferred tax liabilities: | ||
| Fixed assets | (88) | |
| Total deferred tax liabilities | $ (88) |
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from leasehold incentive. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from intangible assets including goodwill. No definition available.
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|