Equity Method Investments - Equity Method Investments Summary (Details) - USD ($)
$ in Thousands

3 Months Ended

Jun. 30, 2018

Mar. 31, 2018

Schedule of Equity Method Investments [Line Items]

Equity Method Investments

$ 11,212

$ 12,016

Equity Method Investments

.

The following table provides a reconciliation of equity method investments to the Company's Consolidated Balance Sheets (amounts in thousands):

	June 30, 2018		March 31, 2018
Nippon Yttrium Co., Ltd ("NYC")	$	7,612	$	8,148
NT Sales Co., Ltd ("NTS")	1,054		998
Investment in Novasentis	2,546		2,870
	$	11,212	$	12,016

Nippon Yttrium Co., Ltd (NYC) [Member]

Schedule of Equity Method Investments [Line Items]

Equity Method Investments

$ 7,612

8,148

NT Sales Co., Ltd (NTS) [Member]

Schedule of Equity Method Investments [Line Items]

Equity Method Investments

1,054

998

Novasentis [Member]

Schedule of Equity Method Investments [Line Items]

Equity Method Investments

$ 2,546

$ 2,870