Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total NxStage Medical Inc. Stockholders' Equity	Noncontrolling Interest Not Subject to Put Provisions
Beginning balance (in shares) at Dec. 31, 2014		63,429,005
Beginning balance at Dec. 31, 2014	$ 191,555	$ 63	$ 593,073	$ (387,488)	$ (2,192)	$ (12,989)	$ 190,467	$ 1,088
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(16,260)
Net income, not subject to put provision	(16,260)			(15,342)			(15,342)	(918)
Adjustments to other comprehensive loss, net of tax	(1,839)				(1,839)		(1,839)
Shares, exercise of stock options (in shares)		1,020,552
Exercise of stock options	6,916	$ 1	7,790			(875)	6,916
Shares issued under employee restricted stock plans (in shares)		306,908
Shares issued under employee restricted stock plans	(943)		(943)				(943)
Shares issued under employee bonus plans (in shares)		66,230
Shares issued under employee bonus plans	$ 1,103		1,103				1,103
Shares issued under employee stock purchase plan (in shares)	50,343
Shares issued under employee stock purchase plan	$ 690		690				690
Stock-based compensation expense	10,774		10,774				10,774
Changes in noncontrolling interest	1,524							1,524
Ending balance (in shares) at Dec. 31, 2015		64,873,038
Ending balance at Dec. 31, 2015	193,520	$ 64	612,487	(402,830)	(4,031)	(13,864)	191,826	1,694
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(7,317)
Net income, not subject to put provision	(7,149)			(4,771)			(4,771)	(2,378)
Adjustments to other comprehensive loss, net of tax	(2,070)				(2,070)		(2,070)
Shares, exercise of stock options (in shares)		658,444
Exercise of stock options	5,914	$ 1	8,233			(2,320)	5,914
Shares issued under employee restricted stock plans (in shares)		314,013
Shares issued under employee restricted stock plans	$ (687)		(687)				(687)
Shares issued under employee stock purchase plan (in shares)	37,531
Shares issued under employee stock purchase plan	$ 767		767				767
Stock-based compensation expense	10,419		10,419				10,419
Changes in noncontrolling interest	1,309							1,309
Ending balance (in shares) at Dec. 31, 2016		65,883,026
Ending balance at Dec. 31, 2016	202,023	$ 65	631,219	(407,601)	(6,101)	(16,184)	201,398	625
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(15,325)
Net income, not subject to put provision	(15,432)			(13,992)			(13,992)	(1,440)
Adjustments to other comprehensive loss, net of tax	$ 2,428				2,428		2,428
Shares, exercise of stock options (in shares)	1,130,939	1,130,939
Exercise of stock options	$ 12,497	$ 1	15,595			(3,099)	12,497
Shares issued under employee restricted stock plans (in shares)		291,601
Shares issued under employee restricted stock plans	$ (1,349)	$ 1	(1,350)				(1,349)
Shares issued under employee stock purchase plan (in shares)	36,253	36,253
Shares issued under employee stock purchase plan	$ 855		855				855
Stock-based compensation expense	11,802		11,802				11,802
Changes in noncontrolling interest	322		(481)				(481)	803
Ending balance (in shares) at Dec. 31, 2017		67,341,819
Ending balance at Dec. 31, 2017	$ 213,146	$ 67	$ 657,640	$ (421,593)	$ (3,673)	$ (19,283)	$ 213,158	$ (12)