Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Taxes [Line Items]
Income before income taxes	$ 12,372,000	$ 13,701,000	$ 4,175,000	$ (1,483,000)	$ 3,762,000	$ 4,651,000	$ 1,429,000	$ (1,312,000)	$ 28,765,000	$ 8,530,000	$ 16,862,000
Reversal of valuation									101,500,000
Valuation allowance	2,912,000				102,093,000				2,912,000	102,093,000
Net operating loss carry forwards expiration period									2016 through fiscal 2034.
Stock-based compensation tax deductions in excess of book compensation expense									606,000
Federal Ministry of Finance, Germany [Member]
Income Taxes [Line Items]
Net operating loss carry forwards	32,200,000								32,200,000
Federal
Income Taxes [Line Items]
Net operating loss carry forwards	175,600,000								175,600,000
Research and development credit carry forwards	11,800,000								11,800,000
Federal | NOLs relates to stock-based compensation tax deductions
Income Taxes [Line Items]
Net operating loss carry forwards	63,000,000								63,000,000
State
Income Taxes [Line Items]
Net operating loss carry forwards	175,600,000								175,600,000
Net operating loss carry forwards expired									1,500,000
Research and development credit carry forwards	$ 5,200,000								$ 5,200,000