Income Taxes - NOL and Tax Credits (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2017 USD ($)
U.S. research credits
Tax credit carryforwards
Tax credits	$ 1,425
Tax Credit Carryforward, Expiration Date	Mar. 31, 2023
Texas franchise tax credits
Tax credit carryforwards
Tax credits	$ 3,122
Tax Credit Carryforward, Expiration Date	Mar. 31, 2026
Foreign Tax Authority [Member]
Tax credit carryforwards
Operating Loss Carryforwards	$ 48,600
Operating Loss Carryforwards Subject to Expiration within One Year	4,800
Tax credits	$ 407
Tax Credit Carryforward, Expiration Date	Mar. 31, 2018
Macedonia
Tax credit carryforwards
Income Tax Expense (Benefit)	$ 0
Domestic Tax Authority [Member]
Tax credit carryforwards
Operating Loss Carryforwards	399,900
State and Local Jurisdiction [Member]
Tax credit carryforwards
Operating Loss Carryforwards	515,800
Operating Loss Carryforwards Subject to Expiration within One Year	$ 5,200
Operating Loss Carryforwards, Expiration Period	1 year