Suncore Joint Venture - Other Disclosures (Details) (USD $)	3 Months Ended			9 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2011
Initital Registered Capital:
Equity Method Investment, Initial Registered Capital, Total Entity						$ 30,000,000
Equity Method Investment, Initial Registered Capital, Equity Partner						18,000,000
Equity Method Investment, Initial Registered Capital, EMCORE						12,000,000
Basis Difference:
Equity Method Investment, Basis Difference, Consulting Fee, Amount Received						8,500,000
Capital Distributions:
Equity Method Investment, Deemed Capital Distribution and Reinvestment, Total Entity		37,000,000
Equity Method Investment, Deemed Capital Distribution and Reinvestment, Equity Partner		22,200,000
Equity Method Investment, Deemed Capital Distribution and Reinvestment, EMCORE		14,800,000
Cash Dividends:
Equity Method Investment, Dividend Distribution, Total Entity		4,100,000
Equity Method Investment, Dividend Distribution, Equity Partner		2,500,000
Equity Method Investment, Dividend Distribution, EMCORE		1,600,000
Foreign income tax:
Foreign income tax expense on capital distributions	0		0	1,644,000	0
CPV Development Agreement:
Equity Method Investment, CPV Development Agreement, Reimbursement Rate				0.00%
Equity Method Investment, CPV Development Agreement, Development Fee Rate				0.00%
Equity Method Investment, CPV Development Agreement, Maximum Development Fee				200,000
Equity Method Investment, CPV Development Agreement, Reimbursed Costs, Total				900,000
Equity Method Investment, CPV Development Agreement, Development Fee, Earned				200,000
CPV Solar Cell License Agreement:
License agreement, expected proceeds over term				2,500,000
Summarized Financial Information:
Equity Method Investment, Ownership Percentage	40.00%			40.00%
Loss from equity method investment	0		(259,000)	(1,201,000)	(846,000)
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	(2,100,000)			(2,100,000)
Equity method investment	$ 0			$ 0		$ 2,374,000