CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities:
Net income	$ 8,247	$ 5,542	$ 16,273
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	1,526	1,437	1,280
Amortization of intangibles	8,005	3,215
Impairment of intangibles	7,402	1,250
Gain on sale of investments and fixed assets	(2,583)	75
Stock-based compensation expense	3,084	3,083	1,432
Other than temporary decline in value of investments	524
Change in valuation of deferred acquisition consideration	271	628
Change in valuation of warrant liability	89	(114)
Recognition of gain on disposition of assets and sale of products	(1,276)	(700)	(700)
Changes in operating assets and liabilities:
Accounts receivable	4,356	(1,449)
Income tax receivable	(1,795)	(1,455)	864
Prepaid expenses and other assets	(71)	7	(229)
Restricted cash		2,134	121
Accounts payable and other accrued liabilities	(1,951)	2,478	(535)
Deferred tax liability	(6,377)	(1,793)
Deferred revenue	(1,430)	(1,986)	(510)
Net cash provided by operating activities	18,021	12,352	17,996
Investing activities:
Purchases of marketable securities	(168,993)	(95,269)	(169,107)
Sales and maturities of marketable securities	138,000	98,551	168,954
Proceeds from sale of products	700	700	700
Purchases of property and equipment	(1,031)	(1,376)	(1,007)
Proceeds from sale of property and equipment		101
Acquisition of Astex Therapeutics net assets, net of cash acquired		(269)
Payment of deferred consideration relating to acquisition of Astex Therapeutics Limited	(12,272)
Net cash provided by (used in) investing activities	(43,596)	2,438	(460)
Financing activities:
Proceeds from issuances of common stock	715	434	336
Net cash provided by financing activities	715	434	336
Effect of foreign exchange rate changes on cash and cash equivalents	568	(990)
Net increase (decrease) in cash and cash equivalents	(24,292)	14,234	17,872
Cash and cash equivalents at beginning of period	39,788	25,554	7,682
Cash and cash equivalents at end of period	15,496	39,788	25,554
Supplemental Disclosure of Non-Cash Investing Activities:
Fixed assets and intellectual property transferred in exchange for investment	924
Common stock issued in connection with Astex Therapeutics acquisition		95,119
Fair value of stock options assumed in connection with Astex Therapeutics acquisition		3,270
Fair value of warrants assumed in connection with Astex Therapeutics acquisition		301
Supplemental Disclosure of Cash Flow Information:
Income taxes paid in cash during the period	$ 3	$ 39	$ 4