Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company used an annual effective tax rate approach to calculate income taxes for the three and six months ended June 30, 2020 and 2019. The annual effective tax rate of approximately 0% differs from the federal statutory tax rate due primarily to providing a full valuation allowance on net deferred tax assets. At December 31, 2019, the Company had federal and California net operating loss (NOL) carryforwards of approximately $162.5 million. Pursuant to Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the Internal Revenue Code), use of the Company’s NOL carryforwards may be limited if the Company experiences a cumulative change in ownership of greater than 50% in a rolling three-year period. The Company has not performed an analysis of changes in ownership for purposes of these Internal Revenue Code sections. Ownership changes could impact the Company’s ability to utilize NOL carryforwards remaining at an ownership change date. The Company’s NOL carryforwards were generated from domestic operations. The federal NOLs from the 2013-2017 tax years will expire between 2033 and 2037 and NOLs from 2018-2019 will carryover indefinitely. The state NOLs will expire between 2033 and 2039. At December 31, 2019, the Company also had research and development tax credit carryforwards of approximately $2.0 million, which will expire in 2036 to 2039. Approximately $0.9 million of these research and development tax credit carryforwards are included in prepaid expenses and other current assets on the Company’s consolidated balance sheets at June 30, 2020 and December 31, 2019, as they are expected to be utilized in 2020 as a credit to offset payroll taxes. The remaining amount of research and development tax credit carryforwards are included in net deferred tax assets. CARES Act The CARES Act includes provisions to support businesses in the form of loans, grants, and tax changes, among other types of relief. The Company has reviewed the income tax changes included in the CARES Act, which primarily includes the expansion of the carryback period for NOLs, changes to the deduction and limitation on interest, and acceleration of depreciation for Qualified Improvement Property. The Company has analyzed these changes and does not believe there will be a material effect on the Company’s income tax provision.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.