CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 4,842	$ 20,749
Adjustments to reconcile net income to net cash (used in) provided by operating activities
Stock compensation expense	568	1,112
Depreciation	771	572
Change in accrued interest on short-term investments	(150)	(296)
Amortization of purchased intangible assets	253	183
Deferred income tax expense	162	263
Other	(262)	(86)
Changes in operating assets and liabilities
Accounts receivable	(9,522)	(5,028)
Prepaid expenses and other assets	(2,970)	(1,773)
Accounts payable and accrued expenses	(745)	12,730
Change in contracts in progress, net (Note 4)	(53,882)	12,538
Net cash (used in) provided by operating activities	(60,935)	40,964
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of short-term investments	(5,000)	(185,000)
Maturities of short-term investments	103,000	145,000
Purchases of property, plant and equipment	(3,691)	(1,863)
Change in notes receivable	225
Net cash provided by (used in) investing activities	94,534	(41,863)
CASH FLOWS FROM FINANCING ACTIVITIES
Cash dividends paid	(3,892)
Proceeds from the exercise of stock options		867
Net cash (used in) provided by financing activities	(3,892)	867
EFFECTS OF EXCHANGE RATE CHANGES ON CASH	(291)	181
NET INCREASE IN CASH AND CASH EQUIVALENTS	29,416	149
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	122,107	167,198
CASH AND CASH EQUIVALENTS, END OF PERIOD	151,523	$ 167,347
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for income taxes	$ 967