Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016 USD ($) Segment	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Significant Accounting Policies [Line Items]
Cash equivalents	$ 9,100,000		$ 16,300,000
Realized gain (loss) recognized on sale of marketable securities	0	$ 0
Aggregate unrealized losses of securities			3,000
Accounts receivable	1,736,000		$ 4,641,000
Assets measured at level 3 on recurring basis	0
Liabilities measured at level 3 on recurring basis	0
Impairment losses	0	$ 200,000
Tax benefits of the stock based compensation expenses recognized	0
Income tax provision or expense	$ 100,000
Number of operating segments | Segment	1
United Kingdom
Significant Accounting Policies [Line Items]
Net assets located in the United Kingdom	$ 900,000
Level 3
Significant Accounting Policies [Line Items]
Fair value of loan payable	10,100,000
C A Nbridge Life Sciences Ltd
Significant Accounting Policies [Line Items]
Accounts receivable	900,000
Biodesix
Significant Accounting Policies [Line Items]
Accounts receivable	700,000
Astellas Pharma Incorporation
Significant Accounting Policies [Line Items]
Accounts receivable	$ 200,000
Minimum
Significant Accounting Policies [Line Items]
Marketable securities maturity term	3 months
Maximum
Significant Accounting Policies [Line Items]
Marketable securities maturity term	24 months
Maximum | Corporate debt securities
Significant Accounting Policies [Line Items]
Aggregate unrealized losses of securities	$ 1,000