Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	IPO	Common Stock	Common Stock IPO	Additional Paid-In Capital	Additional Paid-In Capital IPO	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest (SRX Cardio)
Balance at beginning of year at Dec. 31, 2013	$ 296,335		$ 41		$ 581,911		$ (285,672)	$ 55
Balance at beginning of year (in shares) at Dec. 31, 2013			40,915,130
Exercise of employee stock options for cash	4,399		$ 1		4,398
Exercise of employee stock options for cash (in shares)			652,125
Lapse of repurchase rights related to common shares issued pursuant to early exercises (in shares)			500
Lapse of repurchase rights related to common shares issued pursuant to early exercises	4				4
Issuance of common stock upon cashless exercise of common stock warrants (shares)			40,314
Issuance of common stock pursuant to ESPP purchase (in shares)			28,737
Issuance of common stock pursuant to ESPP purchase	579				579
Issuance of stock (in shares)				7,130,000
Issuance of stock		$ 174,621		$ 7		$ 174,614
Employee stock-based compensation expense	8,514				8,514
Compensation expense relating to stock options granted to consultants	769				769
Unrealized gain (loss) on available-for-sale securities, net of tax	(294)							(294)
Net loss	(137,125)						(137,125)
Balance at end of the year at Dec. 31, 2014	347,802		$ 49		770,789		(422,797)	(239)
Balance at end of the year (in shares) at Dec. 31, 2014			48,766,806
Exercise of employee stock options for cash	11,111		$ 1		11,110
Exercise of employee stock options for cash (in shares)			1,095,486
Lapse of repurchase rights related to common shares issued pursuant to early exercises (in shares)			125
Issuance of common stock upon cashless exercise of common stock warrants (shares)			3,041
Issuance of common stock pursuant to ESPP purchase (in shares)			30,307
Issuance of common stock pursuant to ESPP purchase	837		$ 1		836
Issuance of stock (in shares)				6,463,750
Issuance of stock		$ 271,096		$ 6		$ 271,090
Employee stock-based compensation expense	20,172				20,172
Compensation expense relating to stock options granted to consultants	2,794				2,794
Unrealized gain (loss) on available-for-sale securities, net of tax	89							89
Development Partner's noncontrolling interest upon consolidation	2,927								$ 2,927
Net loss	(226,505)						(226,505)
Balance at end of the year at Dec. 31, 2015	427,396
Balance at end of the year (in shares) at Dec. 31, 2015			56,359,515
Balance at end of the year at Dec. 31, 2015	430,323		$ 57		1,076,791		(649,302)	(150)	2,927
Exercise of employee stock options for cash	401				401
Exercise of employee stock options for cash (in shares)			54,045
Issuance of common stock pursuant to ESPP purchase (in shares)			62,293
Issuance of common stock pursuant to ESPP purchase	1,278				1,278
Issuance of common stock pursuant to RSU and PSU release (in shares)			68,365
Employee stock-based compensation expense	30,285				30,285
Compensation expense relating to stock options granted to consultants	77				77
Unrealized gain (loss) on available-for-sale securities, net of tax	138							138
Net income attributable to Non Controlling interest (SRX Cardio)	930								930
Dividends to Non Controlling interest (SRX Cardio)'s shareholders	(1,700)								(1,700)
Net loss	(269,043)						(269,043)
Balance at end of the year at Dec. 31, 2016	190,532
Balance at end of the year (in shares) at Dec. 31, 2016			56,544,218
Balance at end of the year at Dec. 31, 2016	$ 192,689		$ 57		$ 1,108,832		$ (918,345)	$ (12)	$ 2,157