Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013 Location Entity	Sep. 30, 2012	Sep. 30, 2013 Segment Location Entity	Sep. 30, 2012	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Percentage of cash, cash equivalent and short-term investments invested in money market fund			89.00%		86.00%
Number of financial institution in which financial instruments invested	1		1
Available-for-sale investment amortized cost	$ 4,002,000		$ 4,002,000		$ 9,022,000
Available-for-sale estimated fair value	4,005,000		4,005,000		9,028,000
Unrealized gain on available-for-sale investments	3,000		3,000		6,000
Percentage of prompt payment discount accrued at the time of sale			100.00%
Standard product warranty description			Although allowances and accruals are recorded at the time of product sale, certain rebates are typically paid out, on average, up to six months or longer after the sale. Reserve estimates are evaluated quarterly and if necessary, adjusted to reflect actual results.
Revenue	13,691,000	13,101,000	37,067,000	38,620,000
Unrecognized tax benefits	0		0		0
Stock options, restricted stock units and warrants purchase			14,972,977	12,905,964
Number of business segment			1
Number of geographic area within which the company operates predominantly	1		1
Foreign Exchange
Significant Accounting Policies [Line Items]
Other expense				3,000
Other income	11,000	10,000	9,000
Not Substantive Milestones
Significant Accounting Policies [Line Items]
Revenue	1,700,000	244,000	3,000,000	2,300,000
Substantive Milestones
Significant Accounting Policies [Line Items]
Revenue	0	0	0	327,000
Development Milestones
Significant Accounting Policies [Line Items]
Milestones payment receipt			66,000,000
Regulatory Filing Milestones
Significant Accounting Policies [Line Items]
Milestones payment receipt			58,000,000
Marketing Approval Milestones
Significant Accounting Policies [Line Items]
Milestones payment receipt			80,000,000
Maximum
Significant Accounting Policies [Line Items]
Estimated useful life of property plant and equipment			7 years
Minimum
Significant Accounting Policies [Line Items]
Estimated useful life of property plant and equipment			3 years
Cash and Cash Equivalents | Maximum
Significant Accounting Policies [Line Items]
Short term investment maturity period			90 days
Short-term Investments | Maximum
Significant Accounting Policies [Line Items]
Short term investment maturity period			1 year
Short-term Investments | Minimum
Significant Accounting Policies [Line Items]
Short term investment maturity period			90 days
US Treasury and Government
Significant Accounting Policies [Line Items]
Available-for-sale investment amortized cost	4,000,000		4,000,000		9,000,000
Available-for-sale estimated fair value	4,000,000		4,000,000		9,000,000
Unrealized gain on available-for-sale investments	$ 3,000		$ 3,000		$ 6,000
Walgreens Infusion Services, Inc.
Significant Accounting Policies [Line Items]
Percentage of single significant customer balance to total Accounts Receivables	53.00%		53.00%		50.00%
US Bioservices Corporation
Significant Accounting Policies [Line Items]
Percentage of single significant customer balance to total Accounts Receivables					34.00%
Eli Lilly and Company
Significant Accounting Policies [Line Items]
Percentage of single significant customer balance to total Accounts Receivables	27.00%		27.00%