Stockholders' Equity - Common Stock (Details) $ / shares in Units, $ in Thousands				1 Months Ended		12 Months Ended
	Sep. 22, 2016 USD ($) $ / shares shares	Nov. 25, 2015 USD ($) $ / shares shares	Jan. 29, 2014 $ / shares	Aug. 31, 2014 USD ($) shares	Jul. 31, 2014 $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)
Class of Stock [Line Items]
Stock split, conversion ratio			0.1
Common stock, par value (in dollars per share) | $ / shares			$ 0.01			$ 0.01	$ 0.01
Stock issued in a private transaction, net of offering cost						$ 49,044	$ 76,056	$ 103,949
Offering costs								237
Proceeds from sale of common stock, net of offering costs				$ 101,500		$ 49,044	$ 76,056	103,949
Common stock, shares authorized (in shares) | shares						500,000,000	500,000,000
Stock price (in shares) | $ / shares							$ 23.54
Payments of stock issuance costs						$ 1,000	$ 1,000	$ 237
Transferable subscription right with respect to each share of common stock					1
Conversion of stock, shares converted (in shares) | shares					0.21
Subscription right exercise price | $ / shares					$ 16.00
Common stock, shares issued | shares				6,400,000		45,533,913	41,009,924
Private Placement
Class of Stock [Line Items]
Proceeds from sale of common stock, net of offering costs		$ 74,800
Common stock, shares authorized (in shares) | shares		3,400,000
Stock price (in shares) | $ / shares		$ 22
Payments of stock issuance costs		$ 1,000
Proceeds from issuance of common stock, net		$ 73,800
Common Stock | Rights Offering
Class of Stock [Line Items]
Stock issued in a private transaction, net of offering cost	$ 49,900
Common Stock | Bridge Loan | Rights Offering
Class of Stock [Line Items]
Shares subscribed but unissued (in shares) | shares	4,000,000
Price per share (in dollars per share) | $ / shares	$ 12.25
Offering costs	$ 900
Proceeds from sale of common stock, net of offering costs	$ 49,000
Conversion of stock, shares converted (in shares) | shares	272,733