Note 3 - Fair Values of Assets and Liabilities - Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Feb. 03, 2018	Jan. 28, 2017
Less: Assets available for sale	$ (2,000,000)	$ (2,000,000)
Fair Value, Measurements, Recurring [Member]
Cash equivalents and short-term investments		303,000
Restricted cash	335,000
Total assets measured at fair value	335,000	8,799,000
Less: Assets available for sale	(335,000)
Assets measured at fair value		8,496
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents and short-term investments		303,000
Restricted cash	335,000
Total assets measured at fair value	335,000	8,799,000
Less: Assets available for sale	(335,000)
Assets measured at fair value		8,496
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents and short-term investments
Restricted cash
Total assets measured at fair value
Less: Assets available for sale
Assets measured at fair value
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents and short-term investments
Restricted cash
Total assets measured at fair value
Less: Assets available for sale		(303,000)
Assets measured at fair value
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents and short-term investments		3,715,000
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents and short-term investments		3,715,000
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents and short-term investments		3,505,000
Money Market Funds [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents and short-term investments		3,505,000
Fixed Income Investments [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents and short-term investments		1,276,000
Fixed Income Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents and short-term investments		1,276,000
Fixed Income Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents and short-term investments
Fixed Income Investments [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents and short-term investments		$ 8,496,000
Corporate Bond Securities [Member] | Fair Value, Measurements, Recurring [Member]
Cash equivalents and short-term investments
Corporate Bond Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents and short-term investments
Corporate Bond Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents and short-term investments
Corporate Bond Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents and short-term investments