Subsequent Events (Details) - USD ($)	Mar. 16, 2017	Mar. 11, 2018	Feb. 23, 2017	Dec. 31, 2016	Mar. 11, 2016
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage					19.90%
Subsidiary, Ownership Interest by Parent					80.10%
Subsequent Event [Member]
Subsequent Event [Line Items]
Subsidiary, Ownership Interest by Parent	80.10%
Grants Receivable			$ 12,200,000
Grants Receivable, Current			$ 5,700,000
Hitachi America [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage				19.90%	21.00%
Hitachi America [Member] | PCT [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds From Licensing Agreements	$ 75,000,000
Forecast [Member] | Hitachi America [Member]
Subsequent Event [Line Items]
Proceeds From Licensing Agreements, Initial Payment	5,000,000
Proceeds From Licensing Agreements, Closing Payments	5,000,000
Former director [Member] | Forecast [Member] | Dr. Preti [Member]
Subsequent Event [Line Items]
Related Party Transaction, Payment for Retention Agreement in Connection with Sale, First Retention Payment	1,375,000
Related Party Transaction, Payment for Retention Agreement in Connection with Sale, Second Retention Payment	$ 1,375,000
Related Party Transaction, Payment for Retention Agreement in Connection with Sale, Third Retention Payment, Percentage of Milestone Payment	5.00%
Related Party Transaction, Net Payments for Retention Agreement, Threshold for Tax Reimbursement Payment	$ 1,200,000
Former director [Member] | Forecast [Member] | Dr. Preti [Member] | PCT [Member]
Subsequent Event [Line Items]
Deferred Compensation Arrangement with Individual, Cash Award Granted, Amount	$ 196,112	$ 175,000