Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax [Line Items]
Net operating loss carryforwards	$ 139,700,000
Tax Credit Carryforward, Description	The Company’s net operating loss carryforwards will expire beginning 2025 through 2036.
Valuation allowance	$ 54,779,000	$ 48,620,000
Increase net deferred tax asset	$ 6,200,000
Federal statutory income tax rate	34.00%	34.00%
Reserve for uncertain tax positions	$ 0	$ 0
Interest or penalties recognized	$ 0	$ 0
Open tax year	2009
Research Tax Credit Carryforward
Income Tax [Line Items]
Research and experimentation credits	$ 1,400,000
Operating loss carryforwards, limitations on use	Utilization of net operating losses and tax credits, including those acquired as a result of the Merger, will be subject to an annual limitation due to ownership change limitations provided by Internal Revenue Code Section 382. The Company believes that an ownership change limitation as defined under Section 382 of the U.S. Internal Revenue Code occurred as a result of its various historical financing transactions, and its offering of common stock completed in June 2015. Future utilization of the federal net operating losses and tax credit carryforwards accumulated from June 2005 to the change in ownership date will be subject to annual limitations to offset future taxable income. The annual limitation may result in the expiration of the net operating losses and credits before utilization. As such, a portion of the Company’s net operating loss carryforwards may be limited
Tax credit carryforward, limitations on use	Utilization of net operating losses and tax credits, including those acquired as a result of the Merger, will be subject to an annual limitation due to ownership change limitations provided by Internal Revenue Code Section 382. The Company believes that an ownership change limitation as defined under Section 382 of the U.S. Internal Revenue Code occurred as a result of its various historical financing transactions, and its offering of common stock completed in June 2015. Future utilization of the federal net operating losses and tax credit carryforwards accumulated from June 2005 to the change in ownership date will be subject to annual limitations to offset future taxable income. The annual limitation may result in the expiration of the net operating losses and credits before utilization. As such, a portion of the Company’s net operating loss carryforwards may be limited
Earliest Tax Year
Income Tax [Line Items]
Operating loss carryforwards expiration year	2025
Latest Tax Year
Income Tax [Line Items]
Operating loss carryforwards expiration year	2036