Revenue Recognition - Total Gross Product (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Provision for product sales allowances and accruals:
Contractual adjustments, percent of gross product sales	36.00%	34.00%
Governmental rebates, percent of gross product sales	15.00%	12.00%
Total, percent of gross product sales	51.00%	46.00%
Product Revenue
Disaggregation of Revenue [Line Items]
Gross product sales	$ 239,870	$ 206,724
Provision for product sales allowances and accruals:
Contractual adjustments	86,144	69,829
Governmental rebates	36,378	24,378
Total	122,522	94,207
Product sales, net	$ 117,348	$ 112,517

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130539-203045

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130545-203045

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