Description of Business (Details) $ / shares in Units, $ in Thousands					1 Months Ended	12 Months Ended
		Dec. 16, 2016 $ / shares shares	Nov. 29, 2016 USD ($) revenue_stream drug product $ / shares shares	Nov. 28, 2016 shares	May 31, 2016 USD ($)	Dec. 31, 2016 USD ($) shares		Dec. 15, 2016 shares	Dec. 31, 2015 USD ($) shares		Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Cash and cash equivalents | $						$ 108,927			$ 141,824		$ 155,908	$ 118,521
Number of revenue streams | revenue_stream			2
Stock consolidation ratio		0.20
Accrued liabilities | $						$ 37,180			$ 1,827
Common stock, shares issued (in shares)		18,530,323				18,530,323	[1]	92,653,562	10,565,489	[1]
Common stock, shares outstanding (in shares)		18,530,323						92,653,562
Common stock, par value (in dollars per share) | $ / shares		$ 0
JUXTAPID
Business Acquisition [Line Items]
Accrued liabilities | $			$ 1,000
Litigation settlement amount | $			$ 40,000		$ 40,000
Private Placement
Business Acquisition [Line Items]
Maximum number of warrants exercisable (in shares)			2,644,952
Exercise price of warrants (in dollars per share) | $ / shares			$ 0.05
Shares issued, price per share (in usd per share) | $ / shares			$ 8.80
Shares issued (in shares)			2,472,727
Number of fully paid up warrants			531,208
Shares issuable under warrant transaction (in shares)			568,181	568,181
Common Stock
Business Acquisition [Line Items]
Shares issued (in shares)	[2]					1,904,546
Aegerion
Business Acquisition [Line Items]
Cash and cash equivalents | $			$ 28,700
Number of orphan drug-designated product | drug			1
Maximum number of warrants exercisable (in shares)			11,301,791
Exercise price of warrants (in dollars per share) | $ / shares			$ 0.05
Shares issued (in shares)			6,060,288
Number of warrants issued (in shares)			10,565,879	10,565,879
Aegerion | JUXTAPID
Business Acquisition [Line Items]
Number of commercial products | product			2
Aegerion | MYALEPT
Business Acquisition [Line Items]
Number of commercial products | product			2
Aegerion | Private Placement
Business Acquisition [Line Items]
Number of warrants issued (in shares)			2,472,727

[1] Amounts have been retroactively restated for all prior periods presented to reflect the one-for-five share consolidation of the Company’s common stock effected on December 16, 2016.

[2] Amounts have been retroactively restated for all prior periods presented to reflect the one-for-five share consolidation of the Company’s common stock effected on December 16, 2016.