CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 4,806	$ (28,933)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Deferred income tax expense (benefit)	8,536	(6,722)
Depreciation	1,858	1,711
Stock compensation expense	1,414	926
Lease expense	793	382
Amortization of purchased intangible assets	451	592
Changes in accrued interest on short-term investments	295	299
Impairment loss		2,072
Other	104	43
Changes in operating assets and liabilities
Accounts receivable	7,532	(9,835)
Contract assets	6,856	6,615
Other assets	(17,781)	2,722
Accounts payable and accrued expenses	4,714	(16,445)
Contract liabilities	83,323	(6,591)
Net cash provided by (used in) operating activities	102,901	(53,164)
CASH FLOWS FROM INVESTING ACTIVITIES
Maturities of short-term investments	145,000	104,000
Purchases of short-term investments	(10,000)	(35,000)
Purchases of property, plant and equipment	(1,133)	(3,043)
Net cash provided by investing activities	133,867	65,957
CASH FLOWS FROM FINANCING ACTIVITIES
Payments of cash dividends	(23,499)	(7,803)
Proceeds from the exercise of stock options	725	1,567
Net cash used in financing activities	(22,774)	(6,236)
EFFECTS OF EXCHANGE RATE CHANGES ON CASH	1,067	(165)
NET INCREASE IN CASH AND CASH EQUIVALENTS	215,061	6,392
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	167,363	164,318
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 382,424	$ 170,710