Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Oct. 31, 2015	Nov. 01, 2014
Cash flows from operating activities:
Net income (loss)	$ 6,349,000	$ (18,091,000)
Adjustments to reconcile net income (loss) to net cash used in (provided by) operating activities:
Depreciation and amortization	15,691,000	16,153,000
Stock-based compensation	4,880,000	4,578,000
Provision for excess and obsolete inventory	2,252,000	2,397,000
Provision for sales returns, discounts and doubtful accounts	727,000	368,000
Deferred income taxes	(216,000)	(3,123,000)
Impairment of IP, mask sets and design tools	1,783,000	2,122,000
Tax effect related to share awards	81,000	(620,000)
Excess tax expense from stock-based compensation	(81,000)	620,000
Impairment of investment	132,000	601,000
Other non-cash activities	(267,000)	70,000
Changes in operating assets and liabilities:
Accounts receivable	(5,283,000)	1,313,000
Inventory	(9,760,000)	(2,103,000)
Prepaid expenses and other current assets	98,000	1,598,000
Other non-current assets	(5,953,000)	127,000
Accounts payable	4,321,000	4,141,000
Accrued liabilities, compensation and related benefits	(4,482,000)	5,310,000
Income taxes payable	(1,425,000)	(273,000)
Other long-term liabilities	910,000	(2,428,000)
Net cash provided by operating activities	$ 9,757,000	12,760,000
Cash flows from investing activities:
Restricted cash		275,000
Purchases of marketable securities	$ (22,622,000)	(3,079,000)
Sales and maturities of marketable securities	5,050,000	13,233,000
Purchases of software, equipment and leasehold improvements	(5,551,000)	(5,161,000)
Purchases of IP	(2,750,000)	$ (2,443,000)
Issuance of short-term promissory notes	$ (2,710,000)
Repayment of note receivable		$ 230,000
Net cash (used in) provided by investing activities	$ (28,583,000)	3,055,000
Cash flows from financing activities:
Excess tax benefit from stock-based compensation	(81,000)	36,000
Net proceeds from exercises of employee stock options and stock purchase rights	2,752,000	1,270,000
Net cash provided by financing activities	2,671,000	1,306,000
Effect of foreign exchange rate changes on cash and cash equivalents	(183,000)	(151,000)
Net (decrease) increase in cash and cash equivalents	(16,338,000)	16,970,000
Cash and cash equivalents, beginning of period	83,502,000	64,326,000
Cash and cash equivalents, end of period	67,164,000	81,296,000
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 7,335,000	$ 5,596,000