CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities
Net income (loss)	$ (14,628)	$ 20,892
Adjustments to reconcile net income (loss) to cash used in operating activities:
Depreciation	531	718
Charge for 401(k) company common stock match	268	264
Stock-based compensation	1,677	2,083
Inventory impairment	271
Changes in operating assets and liabilities:
Accounts receivable	503	(362)
Due from related party	75	311
Unbilled receivables	(446)	(217)
Inventory	(263)	(2,821)
Prepaid expenses and other assets	(192)	203
Accounts payable	(1,131)	101
Accrued expenses	(345)	(675)
Deferred rent and other long-term liabilities	(76)	(78)
Deferred revenue	(538)	(38,562)
Net cash used in operating activities	(14,294)	(18,143)
Cash flows from investing activities
Purchase of property and equipment	(270)	(287)
Change in restricted cash	(25)
Purchase of investments	(10,580)	(47,935)
Proceeds from the sale and maturity of investments	22,509	57,207
Net cash provided by investing activities	11,634	8,985
Cash flows from financing activities
Proceeds from options exercised	14	19
Net cash provided by financing activities	14	19
Effect of exchange rate changes on cash and cash equivalents	(18)	(6)
Net decrease in cash and cash equivalents	(2,664)	(9,145)
Cash and cash equivalents at beginning of period	14,572	21,277
Cash and cash equivalents at end of period	$ 11,908	$ 12,132