Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Gross uncertain tax benefit	$ 400,000
Unrecognized tax benefits that would impact effective tax	12,500,000	$ 7,200,000	$ 7,200,000
Income tax, penalties and interest expense	300,000	100,000	$ 0
Income tax, penalties and interest accrued	500,000	$ 100,000
California Tax Authority [Member]
Income Taxes [Line Items]
Reserves recorded against net operating losses	52,700,000
Net operating losses	52,700,000
Net research and development carryforwards	16,200,000
Reserve on tax credit carry forward amount	16,200,000
Federal Tax Authority [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 42,700,000
Operating loss carryforwards expiration year	2018
Net research and development carryforwards	$ 18,200,000
Federal tax credit carryforwards, expiration year	2020
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 106,000,000
Operating loss carryforwards expiration year	2017
Foreign Tax Authority [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 8,600,000
Operating loss carryforwards expiration year	2018