Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Accounts Receivable
Accounts receivable	5,778	5,932
Accounts Receivable. | Accounts receivable balances | Minimum
Customers representing greater than 10% of accounts receivable balances
Percentage required for qualification as major customer	10.00%	10.00%
Accounts Receivable. | Accounts receivable balances | AmerisourceBergen Drug Corporation.
Customers representing greater than 10% of accounts receivable balances
Accounts receivable by major customer (as a percent)	48.00%	44.00%
Accounts Receivable. | Accounts receivable balances | McKesson Corporation
Customers representing greater than 10% of accounts receivable balances
Accounts receivable by major customer (as a percent)	25.00%	33.00%
Accounts Receivable. | Accounts receivable balances | Cardinal Health, Inc
Customers representing greater than 10% of accounts receivable balances
Accounts receivable by major customer (as a percent)	20.00%	15.00%